Generating a Target Image

First, the primitives must be produced (or use the pre-compiled files in the tgz or zip download file, if your hardware is sufficiently similar to mine) by running make to assemble and link riscy.asm into riscy.bin (the binary image of the primitives) and riscy.lnkt (the symbol table output from linker that Lisp will parse to find out the addresses of the primitives).
Then, load the file arm.lisp. The command to do this is in a comment near the top of the file arm.lisp. This loads the other Lisp files that are needed and loads the primitives into the target image and then compiles the Forth high-level source code (files such as riscy.forth and mmc.forth), and finally writes the target image to the file combo.bin. The file arm.lisp is short, so don't hesitate to look at it and change it. You will see where it loads the Forth files, so you can add other Forth files, etc.
Finally, from a shell prompt, download combo.bin to the target using whatever bootloader facility you have available.
Then, to talk to the target, start up the interpreter by executing (INTERP) in Lisp. (Again, this command is shown in comments near the top of the file arm.lisp.)