Placing Ads in SideBar

Hi Tom,

I'm sure this has been asked and answered elsewhere, and I apologize for any redundancy, but I can't seem to find the answer on my own.

I would like to place some banner ads in the sidebars of the pages on my site, towards the top about where my text starts on each page. Does something like this require an add-on, or is this something that is native to Wordpress or the free GeneratePress theme?

I'm a bit of a newbie to all of this and am still learning. I'm sure there's a way to go into the website coding and make changes, but I am no where near to that proficient yet. I'm perfectly okay with purchasing an add-on if that is the answer, I just don't want to spend money on something I don't need, particularly since my site really isn't monetized yet (in other words, it's not making money).

Any assistance is greatly appreciated, and by the way, I love the theme!

Thanks,
Chris