Building Your First AI Video with Runway Gen-3: A Step-by-Step Tutorial

Runway Gen-3 Alpha is currently the most capable AI video generator accessible to individual creators, and it’s a good starting point because the interface is clean, the queue times are reasonable, and the outputs reliably beat what was possible even six months ago. This tutorial walks through creating your first video from scratch, including what prompts work, what to do when the first attempt fails, and how to export the final result.

What You Need Before Starting

You’ll need a Runway account — sign up at runwayml.com. Free accounts get 125 credits to start, which is enough for roughly 8–10 test generations at standard settings. After that, the Standard plan is $15/month for 625 credits (approximately 40 generations), and the Pro plan is $35/month for 2,250 credits.

For this tutorial, the free credits are sufficient. You do not need to download any software — Runway runs entirely in the browser.

Understanding the Gen-3 Interface

When you open a new Gen-3 Alpha project, you’ll see:

• Text-to-video mode: Enter a prompt and generate from scratch
• Image-to-video mode: Upload a starting image and animate it
• Duration options: 5 or 10 seconds
• Aspect ratio: 16:9 (landscape), 9:16 (vertical/mobile), 1:1 (square)

Gen-3 Alpha uses a credit system where a 5-second generation costs 5 credits and a 10-second generation costs 10 credits. At the free tier, start with 5-second generations to conserve credits while learning what works.

Step 1: Define a Specific Scene (Not a Vague Idea)

The most common beginner mistake is a prompt that’s too abstract. “A beautiful landscape” will produce something, but it won’t be controlled or interesting. You need to describe a concrete scene with motion.

Think in terms of cinematography: What is the subject? What is it doing? What is the camera doing? What’s the lighting situation?

Weak prompt: “A forest scene”

Strong prompt: “Low-angle shot through dense pine forest, morning mist drifts between the trees, golden sunlight filters through the canopy, slow camera pull-back, cinematic, 35mm”

The differences that matter:

• Camera angle and movement specified (“low-angle”, “slow camera pull-back”)
• Atmospheric detail (“morning mist”)
• Lighting quality (“golden sunlight filters through the canopy”)
• Style reference (“cinematic, 35mm”)

Step 2: Write Your First Prompt

For your first attempt, stay simple enough to evaluate quickly. Here’s a prompt structure that works reliably in Gen-3:

[Camera shot type], [subject and action], [environment], [lighting], [style/film look]

A few beginner-friendly starting prompts:

Nature scene: Wide establishing shot, tall grass waves gently in the breeze, golden field stretching to the horizon, late afternoon sunlight, warm tones, shallow depth of field

Urban scene: Eye-level tracking shot, busy city street at night, neon signs reflect on wet pavement, light rain, cinematic color grade, Tokyo-style street

Abstract/atmospheric: Macro shot, single water droplet falls in slow motion onto still water surface, ripples expand outward, clean white background, high-speed photography

Choose one and paste it into the Gen-3 text prompt field.

Step 3: Generate and Evaluate the Output

Click Generate. Gen-3 typically takes 60–90 seconds for a 5-second clip. While you wait, it’s worth noting that you should evaluate the output on three things:

1. Subject accuracy: Did it render the object or scene you described?
2. Motion quality: Does movement look natural? Check for flickering, distortion, or objects that morph unexpectedly.
3. Cinematic quality: Does it look like a plausible camera shot, or does it feel flat and generic?

If the first attempt is disappointing, that’s normal. Gen-3 has a nondeterministic component — re-generating the same prompt will produce a different result. Before changing your prompt, try regenerating once.

Step 4: Iterate on Failures

Here are the most common problems and how to fix them:

Problem: The motion is too fast or chaotic Add motion control language: “slow motion”, “gentle”, “static camera”, “minimal movement”

Problem: The scene looks flat or low-quality Add quality descriptors: “8K”, “photorealistic”, “Arri Alexa footage”, “professionally lit”

Problem: The subject looks distorted or wrong Be more specific about the subject. If you wrote “a person walking” and got a distorted figure, try “a woman in a blue coat walks away from camera along a cobblestone street” — the additional specificity constrains the model.

Problem: The background is wrong Move background detail earlier in the prompt. Gen-3’s attention tends to weight prompt content in the order it appears.

Step 5: Use Image-to-Video for Better Control

Once you’ve tested text-to-video, try the image-to-video mode. This is where many creators find more consistent results: generate a strong starting image using Midjourney, DALL-E 3, or Stable Diffusion, then upload it to Runway and animate it forward.

The workflow:

1. Generate a high-quality still image in Midjourney with your desired scene composition
2. Upload it to Runway’s image-to-video interface
3. Add a short motion prompt like “gentle breeze moves through the scene, slow push forward”
4. Generate

Because Gen-3 has a concrete visual reference, it tends to maintain the composition and subject appearance much better than starting from text alone. This is especially useful for character-focused content, product shots, or when you have a very specific aesthetic in mind.

Step 6: Extend and Combine Clips

Runway has a feature called Extend that lets you generate additional seconds appended to an initial clip. You can take a 5-second base clip and extend it to 10, 15, or 20 seconds with continued motion. The results are variable — sometimes the extension is seamless, sometimes there are visual jumps — but it’s a useful tool when you want longer output without paying for a single long generation upfront.

For a final polished video, most creators combine multiple short clips using a standard video editor. CapCut (free, browser-based) is a low-friction option. DaVinci Resolve (free tier) gives you full professional-grade editing including colour grading and multi-track audio — useful if you want to add a soundtrack or sound effects to your generated clips.

Step 7: Export Settings

When you’re happy with a clip in Runway, download it using the export button. Gen-3 exports as an MP4 file at the resolution you generated (1280×720 at Standard quality, or 1920×1080 if you enable the HD option). If you’re posting to YouTube or Instagram, 1080p is preferred. For TikTok or Reels, generate in 9:16 aspect ratio directly rather than cropping after the fact.

What to Expect After Your First Session

After generating 8–10 clips, you’ll develop an intuition for what Gen-3 handles well (atmospheric natural scenes, urban environments, abstract motion) and where it struggles (human faces in close-up, complex hand movements, accurate text rendering). These limitations apply to the entire field right now, not just Runway.

If you want to explore beyond Runway, Pika 1.5 has a free tier with a small number of monthly generations and is generally more lenient about content — useful for testing. Luma AI Dream Machine is free for 30 generations per month and produces notably smooth, physically plausible motion, especially for scenes involving water, smoke, and cloth simulation.

The most effective path forward is to build up a library of prompts that work and iterate on them, rather than trying something completely new each time.