Have you considered the manual to either of those? Seriously. LM4 is the drum vst for Cubase Very simple but you need to step edit or use a midi controller(keyboard or drum trigger. Either will do.)

Acid Pro comes with at least one disc of fairly generic drum loops. There are also probably two other discs of other miscellaneous loops. Those are so simple to work with, you shouldn't need a manual. If you've taken the time to do the built in tutorial, it should be very simple.

If that is yet too difficult for you, you can buy drum loops from many online shops.

http://www.betamonkeymusic.com/index.html

http://www.platinumloops.com/loops_samples.php?cat_id=52

Some free loops here:

http://www.mhat.com/phatdrumloops/beats.asp

If you google "free"+"drum loops" you should get a lot of hits. most of these loops are wav or mp3 format. You should be able to load the loop to a track or tracks. You can iece together a sequence by cutting and pasting loops to create a whole song. then record your guitar. I would just watch the tutorial as suggested.