Good evening!

There is a bug on Season of Discovery.

After installing the addon and it's dependecies, there is no button to open it ingame (addon is working).

Please, fix it <3.

Same here. It also doesn't automatically bind to a key, even though it seems like it's meant to (judging by Bindings.xml file). This isn't the end of the world though. You can find where to bind it in the settings by going to Options > Keybindings > Interface and scrolling to the bottom, it'll just be unbound. Once you bind it to something it works