If your OS is Windows 10, the user folder is C:\Users\USERNAME\AppData\Roaming. The bolded word USERNAME is whatever user name you chose when you set up your device. In the Roaming folder is a folder named Strive. You need to create a folder named mods in the Strive folder. I created a shortcut on my desktop for the AppData folder as several applications put saves and configuration files there.
If your OS is different than Windows 10 I can't help you.