Hey,
yes you can buy from other sides loops and samples but keep in mind that they have to be in formats like mp3, wav, mp4 like files which can handle Cross.
You can also create one samples and also samples in live set like pressing the sample butten when nothing is loaded and you have set like 4-beat it will create a temporary 4-beat loop at a sample section.
To your question about how to set samples: I would prefere you to set them before going to the party. So I mean that you can create sample banks and save them. So you have only to load them for the set.
You can also put them in live set directly with your mouse into the sample decks but I prefere to set them before you start playing
.
You can trigger them also with a second MIDI controller like AKAI LPD8 or your mouse or keyboard. The only thing you have to do is to map the mapping (keyboard or MIDI device).
So if you have further questions ask again.
Attention: PLEASE keep on mind that DRM protected files will not work!
regards
Christian