Just so you know, we have a First Time Mushrooms thread designed specifically for these questions. This thread will be merged with that one once you've had a chance to reply.
Before posting a thread asking questions you should check the
Beginners FAQ and the
Psychedelic Index (these are both linked in big bold writing at the top of this forum) - the Index in particular has lists of all our main threads, and then inside each of those are lists of subthreads. In your case, looking for first time mushroom information, you would go to the Psychedelic Index, search for Mushrooms, see the Big & Dandy Psilocybin Mushroom Thread, then inside the first post of that thread you can look through for any more specific subthreads, and you'd see the "First Time Mushrooms" thread
Others have given some good advice here. I would not advise combining with Cannabis your first time taking Mushrooms. If you're very experienced with other psychedelics and combining Cannabis with them then go for it if you feel it's right to do so, but the mix isn't necessarily a pleasant one for everyone. For some people it makes the trip better, and can intensity some of the good effects while reducing some of the bad ones - while for others it can do the opposite.
If you do decide to smoke Cannabis, I'd recommend waiting until your second or third time with Mushrooms so you've gotten a taste for their character on its own before changing it with another drug.