Adding Repository for Verisure Add-On

I am fairly new to using Home Assistant. Just installed Hass.io on Raspberry the other day and now I am attempting to add Verisure into my Home Assistant. I have searched and read various instructions, but I am stil a bit confused as to how to proceed. I have understood that I first will have to add the Verisure Add-On, but as this is not part of the included repository I guess I have to add this somehow. However, I am not able to find this repository. Is there are collection of repositories somewhere that this is part of or is it a repository a link somewhere just for the Verisure Add-On? I tried using this link, but that did not seem to work as nothing new showed up. Am I missing something? Sorry if this is a stupid question.