Spot on, hence why there are so many adjustment options on them, that's why I said get a notebook and write the settings down, but keep in mind, if there is a big jump/drop set them up to cope with that first, if you don't it could destroy your forks or worse your frame aswell.
No problem mate, basically comprsion is how hard the forks are to compress, meaning that if you have a fast very bumpy track this should be softer so the wheels can track over them calmly without shaking you off the bike, if you have some big jumps or drop offs this should be hard so you don't bottom the suspension out breaking it, rebound is how fast they return to there original position, this is the reverse of above, so bumpy tracks turn it up so the forks return to there normal position quicker ready for the next bump, and for big jumps/ drops turn it down so they help absorb the the hit and don't bounce you off the bike. B-)
Is it better to find a good medium in it when riding Downhill or is it better to always adjust it? The problem with adjusting it might be that some trails have different characteristics right?
spot on mate, that's why I said get a notebook and write the settings down, how I told you before of in the middle is the best place to start, but every track is different, that's why there are so many adjustments available, one thing to bear in mind is that if there is a big jump/drop off, set them up for that, if you don't you could break the forks or worse the frame, ouch!