How do I extend the timing of the Access Point door staying open?

If you go to Sites & Access Points > hover over the gear icon and click "Edit" as shown below.

Scroll till you see Assigned Door Controller (as shown below):

Click "Edit/Assign Devices" button and then you can extend the relay timings to what you want. 7 seconds is the default.

Don't forget to click Save once you have made changes.