The language pack es_ES.phar does not belong in the plugin folder. You should remove it.
It belongs in \include\i18n
Once you put the plugins into the \plugin folder you need to add them to osTicket.
Admin panel -> manage -> plugins
Click Add New Plugin.
Click install on the plugin you want to install.
Once its installed click on the plugin in the list to configure it.
Once you have configured and saved the config you select the tick box to the left of the plugin name, and go to More.
And selected Enable.