Button Menu extension

Install

Download the latest release.
Unzip the downloaded release, and change the name of the folder to buttonmenu.
In the ext directory of your phpBB board, create a new directory named dmzx (if it does not already exist).
Copy the buttonmenu folder to /ext/dmzx/ (if done correctly, you'll have the main extension class at (your forum root)/ext/dmzx/buttonmenu/composer.json).
Navigate in the ACP to Customise -> Manage extensions.
Look for Button Menu under the Disabled Extensions list, and click its Enable link.

Navigate in the ACP to Customise -> Extension Management -> Extensions.
Look for Button Menu under the Enabled Extensions list, and click its Disable link.
To permanently uninstall, click Delete Data and then delete the /ext/dmzx/buttonmenu folder.