It's just my way to do or what i found on forums

If you have a better or easier way to do it, i will very enjoy to know it ;)

1 - Get the package 2D Tilemap Extras (Windows > Package Manager)

2 - Set the grid for each objects (Pefabs) you want to paint, in this case, i need 5  grid (fall, inv, int, tel , push)

3 - Add a Tilemap component


4 - Make sure you have a Tile Palette


5.1 - Select your Tile Palette window

5.2 - Select your Active Tilemap

5.6 - Select your Palette

5.7 - Select GameObject Brush

6 - Select the sprite you need and drag & drop your Prefab in GameObject (Cells)

7 - Now you can paint your Prefabs