You mentioned that you didn’t fully understand the guide, so I’m giving you a more detailed explanation. First, right-click on Euro Truck Simulator 2 in your Steam library and go to Properties. Then, open the "Betas" tab and select “temporary_1_54 - 1.54.x” from the Beta Participation dropdown. After choosing this version, some incompatible mods may activate, and the download will begin automatically. You won’t be able to launch TruckersMP until the download is fully completed.
Guide images
Step 1
Step 2
Step 3
Step 4
Finally
This way the download will start. Once the download is complete, you can enter the game.
Kind regards,
xBARON