Plugin usage

[Big Boy]

Good day, I have some questions regarding the different service plugins. First of all, I don't understand in the documentation how a generated plugin library is linked with the service. Second of all, is the DHTU in summary a plugin for the DHT, in that I get to customize how the messages are sent in the service? And what would be the difference between the plugin_dhtu_ip and plugin_dhtu_gnunet, are they both required if I desire to make changes in the service? Thank you in advance!