Need Help Loading sounds to ALL of the different banks--256?

I am having trouble loading sounds (wav) to my MPC from CDR. I can load up the sounds (individually..one at a time) to the first 64 sound banks, but then there is supposed to be a way to load 4x that amount for a total of 256 sounds. Can you help me figure out how to load to and access the additional sounds to the other banks? Does this make sense? I can't get any specifics from the manual or am just missing the specifics on theis topic. Any help is appreciated.
Thanks.

you can ideed get 256 sounds in RAM however you can only get 64 sounds on the pads at one time
is that what you meant or is your machine only allowing 64 sounds in Ram??

Really? Okay, I guess that since I have the 32 MB of Ram I should be able to get them into Ram and then get the working on the pads thru Drums 1-4? But I am still not clear on how to do that. You should be able to load up the sounds and then access thrm thru switching from Drums 1-4 and ten incorporate them into your beats, correct? If you can clarify how to do that, that would be great. Peace.