Dummy plugin which will just show some info to the Administration user?

Hello,

i have a few questions and need help about creating a very simple dummy plugin for Shopware 6. 

It is just supposed to give some instructions (like a formated box of text) to the user in the Administration part. I already created my composer.json with some needed information and a plugin icon. I can see it in the list of My Plugins and can activate it. I don’t know what to do next here and all the tutorials i checked are not helping me much.

What would be the next step here? What am i supposed to use to just show some information to the user and where should that kind of info be located in the Administration part?
Am i supposed to create a module for the plugin or can i do something more simple?