Add Left Sidebar to Theme Optimizer

I am sorry to bother everyone with this. I have tried understanding from other posts how this works but I am still confused. I do not have very experienced coding knowledge.

I would like to add a left sidebar to the theme optimizer. It seems from research that I will have to insert some code somewhere in the editor, but I am not sure which code, nor where to put it.

I found the sidebar.php file in the editor. I was curious if I could copy this code or file and make a new one. Then inserting it somewhere only aligning it(maybe in the css file?) to the left of the webpage.

Any help would be much appreciated! Thanks!