First you could check out the BOINC Essentials thread. http://www.overclock.net/t/733459/boinc-essentials-thread-check-this-out-if-you-are-new-to-boinc/0_50
If you still have some questions after looking through the various guides, I would suggest starting a new thread. With a new thread you are much more likely to get more detailed help, and it will also helps to keep this thread On-Topic.
In the OP list which hardware you want to crunch on, and i would also list "how" you want to crunch.
For example, do want to BOINC on your GPU, CPU, or both CPU and GPU? Will you be crunching on a dedicated machine, 24/7, while the computer is idle, etc.