Why not start with something simple like . for empty space and # for walls then open Notepad and type a few lines like this which is a 10x10 map?
##########
#..#..#..#
#..#..#..#
#........#
#..#..#..#
#..#..#..#
#####.####
#........#
#........#
##########
Then save it as "map.txt". That would correspond to three rooms and a connecting corridor - or 4 rooms if you prefer. Then use the loading code you used before on your other thread (with the changes I suggested).
Incidentally you haven't replied to the suggestions on your other thread. People may stop helping you if you make too many threads and don't reply to their suggestions.