Hoho - serious stuff for first year electronics!
Don't worry if this is a bit of a mystery at this stage. The most interesting combination of waves is (I think) one that includes the main frequency f, 3f (with an amplitude of 1/3), 5f (with an amplitude of 1/5) etc. That will give you something that gets closer to a square wave as you add higher frequencies ... one to discuss in the pub (or the coffee bar if you don't drink beer!)
Basics of Electronics ... a "Toybox" by Alan Murray, University of Edinburgh is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.