Step by step:

1. Get your animation (use your own or download one).
Make sure your animation is Humanoid Type. Get the animation model prefab and drag it into your scene.

2. Get your 3D character (use your own or download one). Drag the model prefab into your scene. Make sure its skeleton is bipedal and the bone hierarchy is clean and correct. Assign the animation type as Humanoid too.

3. Assign the same Animator Controller or create a new with the same animation clip in the default state.

▸ Animations Pack used in this video (FREE to download)
https://assetstore.unity.com/packages/3d/animations/basic-motions-free-pack-154271

▸ Some FREE 3D Character from the Unity Asset Store compatible:
- Strong Knight
https://assetstore.unity.com/packages/3d/characters/humanoids/strong-knight-83586
- Character Elf
https://assetstore.unity.com/packages/3d/characters/humanoids/character-elf-114445
- Skeleton Outlaw
https://assetstore.unity.com/packages/3d/characters/skeleton-outlaw-130946
- Barbarian warrior
https://as…