You can find all your accesses in the app, under “More.” If you add them as a “Favorite,” you can access them directly from the home page of the app.
You can open doors either by scanning the “Accessy puck” at the door (if there is one), or by tapping the open button in the app. To scan, the app must be in “Ready to scan” mode by tapping the Accessy logo in the middle. The open button may have slightly different names, but is often called “Unlock” in most cases and looks like this: