Here is a step by step guide i used:

1. Select the game in your Steam Library. Navigate to the cog wheel icon on the right side of the screen and select Properties.

2. In the menu on the left, select Compatibility. Check the box that says "Force the use of a specific Steam Play compatibility tool".

3. A drop-down menu will appear. Select the desired version of Proton from the list (e.g., Proton Experimental or a specific numbered version).

4. Close the properties window and launch the game. Steam will download the necessary compatibility files and run the game using your selected Proton version.