Hi,
There are no sampling features on the Prophet X. You need to import existing libraries (e.g. 8DIO or the 3rd party ones here) or you can build your own to import (e.g. using Lady Gaia's PxToolKit (see sticky thread at the top of this forum).
The Prophet X is a great synth, you get that classic Prophet sound and the ability to process samples as well.
I was lucky I got mine at a bargain price that I still cannot believe. I was after a Novation Summit in late 2019, but they were so new they were hard to come by due to their popularity and were selling out as soon as anybody had stock. By chance I saw a brand mew Prophet X at £2,400. A little out of my budget, but I am worth it!

and have not regretted it. A year later on, I now that the Summit as well. Both are fantastic synths and complement each other nicely.