Using the Loop Explorer, you can find and audition the loops on your hard drive. If you like them, select a MIDI track, set the 'Now' time to where you want the MIDI clip then double-click the MIDI clip.
In the PRV (Piano Roll View), you can draw in MIDI clips with the Pattern Brush Tool. It looks like a paint brush.
Clicking the drop-down arrow next to the brush makes a list of MIDI drum loops appear categorized by instrument (but you can use the loops for any percussion instrument, like a snare clip on a tom, for instance).
Select the one you want to try then select the brush and drag it across the grid where you want the clip to play. Don't like it? Delete it and try another.
I assume you mean Studio Instruments Drums? Insert SID with the option 'Create MIDI Source Track' checked. A MIDI track and the SID soft synth track will be inserted. Check that the output of the MIDI track is to SID. Paint some patterns in the MIDI track's PRV. You should hear drums.
I don't have Studio Instrument drums, so I don't know if you have to insert the drum sounds into the SID kit like I have to do with Session Drummer 2, so check the Help files for that tidbit of info.
Also, lower the SID soft synth's volume level. Some of the hits are LOUD and I don't want you to damage your equipment... or your ears.
Edited to add: just realized I'm in the LE forum, so there's a possibility that you may not be able to do some of the stuff I described.
post edited by 57Gregy - 2011/08/19 00:09:17