Please check the user manual first (EN/DE) and find the knowledge base and answers to technical questions in the FAQs of the former eBlocker GmbH.
Is there any plan to produce a youtube-video how to built a Raspery-Pi (4) and how to install the eBlocker software?
There is really nothing to it, since there is really nothing to build if you have a starter kit PI!
Just transfer the software to the SD-card as described in the manual. Stick the card in the slot of the PI and turn it on after hooking it up to the router or switch.
Worked for me and a video would be of absolutely no help here!