After installing the Q-PIN, add an access rule.

More about Q-PIN:

Q-PIN - Time based PIN for Axis A8207-VE Video Door Station (squaretec.com)

PIN has died! Long live Q-PIN! (squaretec.com) 

Create a rule to open the door:

1. Go to System > Events.
2. Under Rules, click + Add a rule.
3. In Name, enter Open door.
4. In the list of conditions, select Entry list > Access granted.
5. In the list of actions, select I/O > Toggle I/O once.
6. In the list of ports, select Door.
7. Under State, select Active.
8. Set the duration to 00:00:05.
9. Click Save