Greetings,
after testing this Mod which is great ist reduces the amount of space you need to a bare minimum.
I set up a MK 1 building and picked it up again in the inventory but now it's inactive. How can i make it active again?

"Inactive" just means that it's a factory building you've already placed and not a brand new one. Place it down again to reactivate it.

Hi.
I did that but i couldnt get inside. Now after building another Mk1 and 2 Mk2 the (inactive) naming is gone and it works normally.

That's weird. Can you describe what exactly you did to cause this to happen, for example how you placed or picked up your factory building? Did you use manual mining or robot deconstruction or both?

I placed it outside my base out of mistake and repicked it (right click holding and waiting) so that i can place it inside my base. Then i put it down on an iron ore field near my omega Miner to place my Electric Furnaces MK2 (Advanced Mod) inside to reduce the amount of space i need. But I saw on the inventory that it was (inactive) then i placed it and i couldnt enter still named inactive and repicked it again. Then i used the Mk2 i build and placed it and then placed the Mk1 into it still inactive. Then I build 1x MK 1 and 2x MK2 and then it was no longer inactive. Through the whole time I researched your mod.

Can i somehow use 1 Beacon to infuse 4 Factories or do i need to place the beacons inside each factory like i do it outside near the normal buildings.

edit:
I have redone it now a few times i cant reproduce this bug, error or whatever. Maybe the error was behind the screen :-)