Click 'add room' and select a room type to add, once you have, use the arrow keys to move it, and space to place. I recommend adding all doors afterwards.
This is for the game 'FTL', highly recommend it! http://ftlgame.com/ I needed a program to do this, couldn't find one, so I made one, and thought I might as well share it. Using scratch, in 2015? past me wouldn't believe it. This one is identical to the last, except from the rooms being half size. This one is used to make much larger ships. 04/05/15 Change: added remove button added door effect when placing
