Generally, i find it's better to do your own notes :uhhuh: Other people's notes sometimes just end up confusing you especially if they are not there to explain them to you. I did a set of notes on them a while ago if you want them but i doubt they will help if you don't understand understand it already.
Exactly what part of it are you having trouble with?
permutations and combinations is a year 12 3u topic, genraly one of the harder one. not that it is that hard althou im questionin the point of teaching it so early in a preliminar course???