@arturas I’m not sure if the sitemap is usable through HABmin, but you should be able to control the plug through Basic UI or the iOS/Android App (as you have already found out).
Basically you need two things, an item definition and a corresponding entry in your sitemap definition.
It looks like your plug also provides a channel for total active power. You should be able to use it by defining an item for it like this:
Number OsramPlug01_Power "OSRAM Plug 01 Power [%.0f W]" <energy> {channel="COPY THE CHANNEL LINK FOR ACTIVE POWER FROM THE THING"}
And a sitemap entry like this:
Text item=OsramPlug01_Power icon="energy" label="Plug 01 Power [%.0f W]"
Note: I’m configuring items and sitemap entries through the config files, but you should be able to create them in HABmin/PaperUI as well, if you prefer that.