I second MPC Tutor and Lampdog’s suggestion (and just about everyone else here would recommend the MPC Bible).
Like Lampdog said, you don’t have to register the X but I would if I were you. There’s literally hundreds of dollars of free MPC Expansion packs that you can install in your standalone hardware, along with the MPC software and plugins that run in the software (not on the hardware).
Other than that, try reading the manual that comes with it when you register on Akai’s website (the full 409 page manual, not just the Quick Start guide). I would also recommend watching Akai’s YouTube tutorial series videos, along with other Akai users videos for helpful tips and tricks.
MPC Tutor put a lot of work into the Bible, that’s why it’s not free. He also hosts these forums, with no financial support from Akai, so look at your $39.95 investment into helping you learn your gear better than Akai’s manual and keeping these forums going.
I also have an MPC X that I purchased last April (2019), and after spending about $2000 US, I was happy to spend another $40 (a drop in the bucket) to effectively learn the gear in easy to understand terminology and get my money’s worth out of the expensive investment.