To enable the expert menu, it is the same as the V3. To start, menu twice to get the expert menu. Go down to Configure>Menu, and check Expert only. From here on out, the 6 block menu will no longer come up.
Low Boy, does this help? Not item specific as that's already been documented elsewhere, but this is the general flow of the menu.
Program: For program options. So, if you want to change programs, restore, delete, copy, etc, you go to program
Discrimination: These are all the discriminate options - accept/reject VDIs, hot rocks, bottle cap reject
Audio - anything related to audio: Setting up volume, balance, VDI tones, all metal, mixed mode, discriminate audio, VCO
Tracking - track stuff like auto track or lock track, inhibit, offsets
Frequency: frequency options - single and which one or 3 frequency, how VDIs are calculated best data or correlate and the options with those
Filter: Filter selection, and a couple other things
Sensitivity: Disc sens and all metal sens, rx gain, tx boost - those things that deal with how sensitive the machine is.
Configuration: Screen displays, menu options, battery selections, - the basic selections on how to set up the rest of the machine.
Thebeepgoeson made a spreadsheet (based off the one in our user's manual) that has the different menu sections highlighted - linked from the reference links. Earthmansurfer also made a pretty nice list.