Coller Theme Edits

I am using the Coller Theme from WordPress to create a website for the company I work for. I have a couple of things that I would like to edit, per request of my employer. First, we would like to have the site’s navigation as a fixed navigation that would accompany the user as they scroll down the page. When I try and edit that feature, I can’t seem to get it to cooperate the way I would like. It really would only need to be for the desktop version, since the mobile versions will convert to the menu icon, but any help with this issue would be greatly appreciated. Second, the footer currently only contains a second site nav as well as the site info, aka powered by wordpress etc., but I have hidden the credits in the css. I would really like to be able to add things to the footer like other links, logos, and other misc items my employer would like in the footer. If there are any suggestions and help that anyone can provide for either, or both, of my issues, I would greatly appreciate it.