In the plugin administration you can install/deinstall and activate/deactivate existing plugins.
You find the "plugin administration" under "sub menu/miscellaneous".
To install a plugin it must be exist in the right directory. If you will install a new external plugin, copy it into "./PyLucid/plugins_external/PLUGIN_NAME". After this it should be displayed in the plugin administration under the block "not installed".
With a click on the "install" button, the plugin would be insert into the databases (only some meta information would be inserted)
After this the plugin entry should be listed under the block "registered and unactivated".
All plugins listed in the block "registered and unactivated", are installed, but the flag it set to deactivated.
With a click on the button "activate", the plugin moved into the "activated" block and now you can use it with PyLucid.
You can only deactivate a plugin. So all plugin meta data (e.g. the plugin preferences) remain in the database. But the plugin can't be used.
All plugin listed in the block "registered and unactivated" can be deinstalled completely with the button "deinstall". This will remove all plugin data from the database (e.g. the plugin preferences).
All plugins listed in the block "acivated" can be reinit. The reinit procedure deinstall a plugin and install it again in one step. Sometimes this it needed, if a plugin changes the used preferences.