Trying to Add a Sidebar to Header

I’m using the Twenty Eleven Theme, Version 3.4.2

I would like to display google ad links on my header in the same way this website does: https://www.securityguardtraininghq.com/

Here is the link to my website: https://www.bestconcealedcarrygun101.com/

I have read several posts related to this problem, but can’t seem to find one that tells how to add a sidebar widget to the twenty eleven header (I think that is what I need to do here). Some of the posts I have read talk about not making any changes to the twenty eleven theme without creating a child theme. I don’t know what a child theme is or if I need to create one in this case. I have added several plugins to my theme already and have not created a child theme, is that bad?

I would appreciate any help and hope I have not wasted your time by asking a question that has already been addressed. Thank you.

I was hoping that this problem was easily fixed by downloading some kind of header plugin, but have been unable to locate one. I found one called Custom Widget Area, but it was not tested for my version of wordpress and did not seem to do what I needed.