how to upload instruments, etc. from your Native Acess to Machine plus? Do you have to upload them to your computer first the transfer them to the memory card? Are they all compatible ?
You don't, just install it from the M+ itself: Settings>Library.
Settings
Library
No, not even close. What is compatible is listed on the product page under Sounds, note that only the stuff that has an orange + in the corner actually works in Standalone mode.
how about the expansion packs, don't see any red crosses?
The orange crosses are there in the M+ page I linked but it doesn't matter much, all Expansions are compatible except Prismatic Bliss (because it has Rex files).