Don't wait another second, get started with it as soon as possible! (grin)
I think the manual is your friend - having said that, though, I'm a firm believer in just plugging the thing up and seeing if I can use it without reading any docs. If it seems intuitive without reading docs, then I know I will not have a problem understanding the finer details that the manual covers.
The biggest thing that I think you have to consider before just diving in is realizing that the presets that come with the unit are largely slanted towards "FRFR" ("full range flat reponse" or "full range frequency response") use - in other words, you plug the output of the AXE into a studio monitor or PA speaker (via DI box/mixer or whatever), NOT a guitar amp or amp/guitar cab. If you have a set of studio monitors, or a full range PA setup, then plug it in, and just try the presets. If you want to plug it into a guitar amp, then you're going to have to tinker with many of the presets (since they already have amps and cabs built into them).
The next thing is using the input trim (I/O button, etc) to set your level properly. I started out with my PRS SE (humbuckers), so I already had lots of level, and didn't have to tweak anything to get started.
Don't worry about understanding everything - you'll pick that up as you go along.
BTW - the manual, forum, and wiki use what I would call "new" terminology - for example "FRFR" - because the flexibility of the AXE FX could be/is a game changer, and it is usable in a lot of new circumstances. As an example, you could conceivably ditch all or most of your existing pedals and amplification and replace it with the AXE FX. Or you could choose to use the AXEFX simply as a pedalboard replacement, and skip the amp modeling. So looking at the hookup diagrams and thinking about the possibilities is going to be important, once you've gotten your bearings with it.
HTH,
John