Ok. So you aren't building the system from scratch. That is good. However, if you are writing the boot loader for this disk-on-module then you need to know the basic BIOS API's. The PC BIOS is a standard that all BIOS vendors follow. You load a register, trigger an interrupt, and it does something. To read the disc, you load a specific register (dx I think, but don't remember) with the offset of the sector that you want, trigger the interrupt (10h I think - but again may be remembering incorrectly), and the BIOS routines will seek to the sector, read it into a known memory location (don't remember that either - note I haven't done this for about 20 years), and return. You jump to that memory location, and start executing the code there.

In any case, this is not a job for newbies. You really, really need to do some research and learn about this stuff if you are going to get this project done successfully. I'm not here to do your job for you, but I hope I have helped point you in the right direction.