1.1 You can Select a single theme to install/update 1.2 or you can make a multi select with ctrl(strg) or by draging the mouse over
2. You can even select one or more themes and press 'GitHub', then your Browser will open the GitHub Pages from the creator of the theme
Download Updater/Installer from here:
If you want your theme added just PM me on TS5 Wargamer@myteamspeak.com,in the forum or make an issue, then i can add your theme to the source code.