There are two main ways to do this.
One would be, open up FPC and select the preset "Empty", then load your samples into it. You will be able to control them from the piano roll.
Or, you could create a channel for each sample and use the step sequencer to sequence them.
When working with breaks, use Slicex or the Fruity Slicer. This will dump the break into individual hits on the piano roll.
Search Youtube for some tutorials.