It's pretty simple. First, you have to make the screen itself. This is the easy part. Just make it whatever you want it to look like, and save it as a bitmap. Now, you need to list that bitmap in your game. (i.e.
turf
selection
icon = 'selection.bmp'
then you need to make other turfs that do the clicking
turf
new_character
Click()
Make_Character_Proc() or whatever proc you want it to do. do this for the other things like load and stuff.
now then, go to your map, and insert your turf 'selection', which is a bitmap. then, on the parts of the bitmap where you drew your selection boxes, insert the corresponding turfs (like new character turf on the part of the bitmap that has the new character box) remember; turfs don't have to have an icon, so nobody will be able to distinguish the different selection turfs on your bitmap.