Hi there

,
I wonder what qualifies a cleared place as a place you can build on, an appear in your personal list of places? So far there are six places I am developing (keeping safe and with people happy, and with extra beds to welcome new settlers). I have used stations in other areas that now are cleared, but they don't show in my pip boy list, only on the main map.
Maybe it's necessary to plant or build something? Or is it a quest related thing?
I was able to connect several settlements with trade lines, and occasionally ask someone to move to a place that needs more hands.
I recently went to Diamond City and wanted to set a trade line to that place, but the game did not give me the option (cause Diamond City is not clean - due to Parkview and its tough mutants. If I peacefy it, will I be able to do it?)


This brings me to my next question.

From what I heard and what I watched on YouTube, there are about a dozen possible companions in this game. Now I was wondering if I can assign each to a place to which he or she has more affinity, or if I should keep them all in Sanctuary. I know I can send them to the places in my list (of colonies), but I do enjoy having them around.
Any thoughts?

You have to activate the workshop (not a workbench like the "weapons Workbench"). Not all locations with crafting stations have a workshop.

If there are any characters within the build area you also need to be allied to them (have completed their quest) befor you can activate the workshop. Alternatively you can kill them and then activate the workshop.

You can assign companions however you like. There are a lot of reasons for and against any particular setup but they're mostly personal preference.

Thanks, I will check it out. That means tons of possible new places to develop!