Need a little help getting theme and other items setup

I’ve made a couple of stabs at this by myself, but invariably I’ve managed to break one item or another in the list and I don’t fully understand how/where child themes come in here. For example I’m missing a hamburger menu on one of my themes and at this point I’m not sure what I’m missing.

Basically I’d like to add a couple of themes for users along with the hamburger menu. Simple enough right? But I also need to make sure I have the facebook pixel in each theme as well as a menu.

Can someone walk me through the process/order of operations that I should do to make this happen?

Put the Facebook code in one theme. In the other themes, at the bottom of the page is a selector to include other themes.

And maybe you want this? Hamburger Theme Selector