1st I'd start with the forum search:
https://www.esoui.com/forums/search.php
Type in "hide addon"
And you will find a list of many same threads, e.g.
https://www.esoui.com/forums/showthr...ght=hide+addon
Beside that check the WIKI, like Votan already provided the link to the tutorial step showing you how to do it.
And here is another direct wiki entry about this:
Fragments in a scene: On fragment state change (e.g. Hide control as menu opens)