Need helping removing Viagra ad that is on every page of site

Hello,

I have recently been put in charge of the website for a coalition I am on. I did not create the site and am new to WordPress and website making so I don’t understand many of the answers I read to the problem I am having.

I just tried to put some new content on a few of my pages and now there is a viagra ad that shows up either on the bottom of the page or in the right sidebar. I don’t have any idea how to remove this because it isn’t showing up under pages when I try to edit it.

Here is my site:
https://www.glbtdvc.org

Please use the most basic language when responding to this. I don’t know how to edit CCS or what .php means or anything so as easy as possible would be really helpful!

Thanks