1) You do as brokenmann says and you will success.
2) My experience is, you must extract any 003-*.xzm and look under /var/log/packages (slackware) or its equivalent (others) to see what is included in a typical module. Search for startx or similar to get started and add missing files as required. Most important will be to find quickly the missing libraries, etc, files, that the /tmp/start.log ask you for, so you get a desktop running soon. I do a double bookkeeping: I put every file on the live side of Porteus and test it; if it works, I put a copy of it in a "pool" with full path. When you have it ready, you squash the "pool" into your module and you are done! (The pool is normally rootcopy).
3) Some tricks you learn by doing. You will learn how to manage the environment, you will understand concepts like IPC, permissions, and...and... The learning curve is almost flat at start, but it will become steeper and steeper when you know you have mastered the previous step and the next one no longer seems so frightening as it saw before....
...and the virtual box saves much, much time. You can start loosing the fear to use it.
Run all versions of Porteus (download the iso's) in VB to get acquainted with it.
P.S. "Porteus is not only an OS, it contains also a personal philosophy"