No, there is an on screen list. Look for the boxes "GCode" and "MCode" and click on them.
Most are self explanatory, but to get a better explanation, trying "googling" GCode and see what it comes up with. There are one or two articles for free that you can read. It usually gives the syntax for the more complicated ones.
THESE ARE SHOWN ON THE "MILL" SCREENS - NOT THE "LATHE" SCREENS 1024.SET. YOU COULD USE SCREEN 4 AND COPY THEM ACROSS