Saber 40
First of all welcome to the Forum.
FPSC is a bit confusing at the begining but you will soon get the hang of it and your question has been answered many times before.
The doors you see in the 'entity' section should be ignored because they have to be there for the doors in the 'segment' section to work correctly (I won't go into detail about this), but you can still use them just for wall decoration.
You will find that the windows in FPSC will also work in the same way.
It's worth trying the 'search' function at the bottom of the page here in future before asking questions because lots of first time users questions have already been covered and answered in the past and you might get your questions answered more quickly this way.
Also, it's worth downloading 'Nickydudes' Hints and Tips PDF for FPSC which you can find at the link below here.
Have a great christmas and a cool new year.
http://forum.thegamecreators.com/?m=forum_view&t=93081&b=21