Free sticky/floating menu/button to the top of the page

Some of my pages are way too long. But still I want to keep them as single pages.

Is there a plugin or some code to add to get a single sticky button that’s always present on the top right part of the screen, then when pressed navigates to the top of the page? (I use pages, not posts).

I did have a look at some plugins, but I couldn’t find one that did this and nothing else.

The page I need help with: [log in to see the link]