Different slots alone are not enough. When you want different samples (or different machines) on the tracks you need to use different parts.
Parts are like Kits on the A4 or Rytm. They store which machines are used and how they are configured. When two patterns use the same part each reconfiguration will influence both patterns.
I suggest you should read Merlin’s Guide and/or the manual’s sections about parts.
(There are also other methods to use different samples on the tracks like sample chains or sample locks … but I guess that is too advanced for now … the standard way is to use different parts)