Build a door at Minecraft?

Hi, I want to build 2 blocks at Minecraft and a door on it so I can build lockers. But somehow I can't open the door on the two blocks. Can somebody help me? Or is it not because I play on my cell phone?

You have to build the door first and then the blocks and you have to stand the wrong way round

It works if you put the door first.

Otherwise I don't know.

With doors, it depends on which direction you are facing the door so that it is aligned. It is best to set the door first, then the other blocks, that should work better