If you simply start playing through the Main Quest of Fallout 4 like normalyou can find the 'City Manager Holotape' and a bunch of ASAM Sensors required for building plots in the same place you first meet Preston in Concord - Museum of History so very lore-friendly. Once you find the 'City Manager Holotape' and load it in your Pip-Boy it will officially activate the Sim Settlements mod and you can officially start using Sim Settlements to build your settlement s. Sim Settlements needs for you 'find' the Sim Settlements holotape called 'City Manager Holotape' in game before you can start using Sim Settlements. If not, please do that now or at least make sure to do it before you try to do any of the actions or follow any of the suggestions on this page.
Important Note: the assumption of this page and it's content is that you already have the core 'Sim Settlements' mod installed and enabled either Sim Settlements or Sim Settlements Lite.