Use CalcGS to edit each map. Make sure to open rage.gst to start with the
right tileset and a sample map. In an assembly file (.asm), put this code:
.org $9D95 .dw $C9,"SSJ",X .end
Change X to however many maps you're adding, 1 to 255. Each map is a 12x8 set
of bytes (valued 0 to 10). When you're done compile it to an 83+/SE or 84+SE
program. Notice the .db $C9. That value makes sure that when idiots try to run the
program it simply does nothing.

Here's a full sample:

The bottom and top rows of each map shouldn't have a 0 in them!
The character should start at (1,1) : that's the 2nd row, 2nd column. It must be a zero.
All maps MUST be solveable.