Its really easy.
First take any wav format sample, it has to be wav, no mp3.
Once you have your sample, bring up your PSP on your pc and access your kick folder. Access drums folder, then access rel folder.
Once inside the rel folder you will see the wavs that are with the program, take one of the waves out that you do not use ( I took out lowtom.wav) and get it out of the folder.
Then rename your wav that you want to input the the file that you took out (ie, I took out the lowtom.wav, so I renamed my sample that I wanted to put in lowtom.wav)
Once thatís done open launch PSP kick from your PSP, then whatever sound you replaced your original wav with will be your sample (ie, since I replaced lowtom.wav my new sample will be lowtom when I sequence it)
I would like to say thanks for the PSP Kick group, this program is great.
ps- i posted to the hack thread but this thread is more suitable for this type of information.