canon MX 340 printer how can i get it to work with my new macbook pro

How can I hook my aunt XFree 40 Canon printer up to my Wi-Fi? I was sure that I had it working when I first bought this new MacBook Pro two weeks ago, but it does not seem to work it says it has no connection.I tried to print and a document tonight but it did not work.This is the first thing I have needed help with, I have always used Windows operating system. My family especially my grandchildren talk me into a Mac Book Pro.

Ken