Building a network using a MBP for dummies.

Ok this is the situation.

I have a MBP, a Toshiba laptop, a HP desktop and Belkin wifi router, and Xerox 3-in-1 printer.
Could anyone give me instructions on how to build a network so all 3 computers can be on a network. I would like to share files and so on.
Please, I am not much of a tech person, so hope the description can be idiot proof.

Thanks!