To add custom animations in Roblox, start by creating a character rig. Open Roblox Studio, go to the Avatar tab, and click on Rig Builder. Make sure R15 is selected and choose Rthro Normal.
Next, design your animation by opening the Animation Editor under Plugins. Select your rig and create a new animation file. Use keyframes to set each pose, adjusting with the Rotate and Move tools.
After designing, export the animation. Save it by clicking the … button and choosing Save. Then, export it by clicking the … button and selecting Export. Copy the animation ID.
Now, script the animation. Create a local script in the StarterCharacterScripts folder. Use the `LoadAnimation` function to load your custom animation. Link it to actions like running or jumping using events such as `Humanoid.Running:Connect`.
Finally, apply the animation. Add the script to your character and replace default animation IDs with your custom ones. Test the animation in-game to ensure it works smoothly.