Sometimes the primary mouse/trackpad button will swap from the default of Left to Right.
1) Open the Settings app from the start menu (click on the Windows icon at the bottom-left side of the desktop after you log in. Click the Settings cog or type Settings after clicking on the Windows icon.
2) Click on Devices (or type Mouse into the search box in the Settings app)
3) In the Mouse settings, select Left from the drop-down selection beneath Select your primary button. The primary button will change to the option you select.