First open Steam.

The handle presses the guide key between pause and sub-pause. This key is also called differently on different handles. Or click out of the Steam menu and select the big screen mode. (Win10 defaults to the "Watermelon button" in the middle of the Xbox controller to call out the game bar instead of opening the big screen mode. In Windows Settings-Games-Game Bar-use this button on the controller to open the game bar and click on this option Just drop it. But this game bar is actually very convenient, you can record games and other operations, the choice is still up to the player.)

IT House Academy: How to buy gamepads and how to use them correctly

After entering the big screen mode, click Settings in the upper right corner-Controller Settings, and select PS4 Configuration Support. (Steam controller can omit this step.)

IT House Academy: How to buy gamepads and how to use them correctly

Then you can play, Steam will automatically map the handle buttons to the Xbox handle buttons. (In fact, there are also games that natively support DS4 controllers, but very few. After selecting PS4 configuration support, these games will also recognize DS4 controllers as Xbox controllers.)