How to play two different programs on one sequence

I am fairly new to this forum and the mpc 2000xl. Sorry if i sound so dumb, bare with me it's hard for me to explain!!!
But everytime that i load up two different programs
When i want to record let's say

Track 1: Sample melody (program 1)
Track 2: Bass line (program 2)

everytime that i want to record the bassline (program 2) after recording the sample melody (program 1) the program changes
so it's either the bassline or the sample melody that i'm hearing, and sounds like a mess if I put the program 2 as it plays the melody of the program 1 i just recorded but with the bass line (program 2) sounds, Get me?????

the point is:
I can't seem to play 2 different programs on one sequence
hpw can solve that problem??

and also
How, when i slice sound the sample in the zone menu, can i do to make it slice the sound on the pad B, C or D ??

Please help meeee
I'm desperate
Have a nice weekend

put the program on a different drum.

so put pgm 1 on drum 1
pgm 2 on drum 2

then select which drum you want to use on which track on the bottom left of the main screen

Works absolutely great
A million thanks to you
I owe you big time
Have a nice weekend++++