You can enable and disable plugins from the Plugin Management screen.

By default, each plugin is inactive, and you need to explicitly activate a plugin in order for it to become functional. Deactivating plugins can be useful when faults and errors occur; plugins can be activated one by one to trace faults.

There is currently no interface to delete plugins and their files from within GetSimple. If you want to remove a plugin, you can use an FTP client and delete a plugin's files & folders from within /path/to/getsimple/plugins/. Deleting a plugin's file(s) will automatically disable that particular plugin.

Please note: Most plugins save their data inside the /path/to/getsimple/data/other/ folder. Leaving data files in here from removed/disabled plugins usually will not harm your installation, but it would be best if you removed these at the same time as you remove the plugin.