To install the extension download the current tomabom.xpi file. If you try to download it with Mozilla Firefox the download might automatically start the installation process. If not just open your Firefox Browser and drag the downloaded file into the Browser window. You have to restart Firefox in order to complete the installation process.
If you want to uninstall the extension you have to navigate to your add-ons and push the uninstall button next to the ToMaBoM extension. The uninstall process will be executed if you restart the Browser. It might be possible that the uninstall process does not remove all ToMaBoM files from your system. Please check in your profiles folder (e.g., C:\Users\Dieter\AppData\Roaming\Mozilla\Firefox\Profiles\9l3twdyd.default) if there is still a folder called "tomabom". If such a folder exists you can delete this folder manually.