I'm gonna help ya'll out since the Fantom Xpert vanished...
Quick run through on one way to do this(could be other ways of course)
Import samples from PC:
1)Put the X in storage mode
2)Choose whether your using pc card or internal memory.
3)On your PC, Navigate to the /tmp/audio_import folder.
4)Drag all the samples you want for the kit from your PC to this folder (providing you have enough sample ram)
5)Exit PC mode from the PC FIRST (click the 'safely remove harware' icon in the taskbar)when its finished, press 'Patch' on the X to go to the Patch screen
Import samples to sample ram:
7)Press "save/load", then press F8 "import audio"
8)Select Navigate to the tmp/audio_import you saved those files above. (select user or card mem)
9)Press F5 to "mark set" each file you want. If you want to select all the files (or the majority) press Shift then F5 "mark set all"
10)Press F8 "import audio"
Create Rhythm kit:
You should now be in the sample list window. Scroll up to the top (so you dont miss any samples if you had gaps in the list)
11)Press F5 to "mark set" each sample(individually!) with status "New" (Shift F5 "mark set all" works here too, but you might select some wrong samples)
12)Press F7 "load" then F4"create rhythm"
13)Select Pad part
14)Press F8 twice
15)Kit created, press exit
Save samples/Reassign pads (optional):
16)Press "pad settings" if you want to reassign the samples on the pads. Otherwise:
17)Press "write" then F2 "patch/rhythm'
18)Name your kit, then 'enter'
19)Now if you dont have a pc card, you will have to overwrite one of the preloaded user rhythms to store yours. Pick a choice, save kit.
20)Now save the actual samples:
Press save/load, then "save all samples"
-Done-
You can choose your new kit like a regular preloaded kit.