Links to site homepage on every blog page

I have created a blog that is part of pre-existing site. To connect the blog back to the index page of the main site I use some links in a category I made.

Problem is – these links only show on the blogs index page. As soon as you navigate into the blog they don’t show.

What I want to do is have links on every page in the blog point to the homepage of the main site, so people can quickly get back to the entrance.

Any help – very much appreciated.