Howto insert plugin keyframes?

I activated the displaying for plugin keyframes and I understand that plugin keyframes have to be managed by the plugins.

I cannot find any possibility to insert and controle keyframes within the plugins.

What am I missing?

edit: It works when you create these plugins while tweaking the plugin after you have activated the horizontal key symbol above the timeline.

It becomes really enjoyable once you got your first golden key :blush: