It's a pull up door, I bought the d20 add a motor chicken door opener. Timer needs 2 on and 2 off settings. Opens at 5:30am and closes at 9:00pm.Just a simple lamp timer.There are a lot of videos on YouTube on this motor.I got mine on ebay.
I used a 2x4 flat side down I put it about 10 inches off the wall my coop is similar to yours not a lot of headroom my roosts are tall enough so the girls can walk under them it hasn't been a problem at all.