People

To recruit more people to your workshop, you need to build a Recruitment Beacon from the Power option in Build Mode. This beacon requires one power so you can just build a small generator (Generates 3 power). After building the beacon and generator, attach the wire so the generator can power it up. The beacon will remain active and you have the option to manually deactivate it.

People are your main resource in any workshop. They need to be assigned to tend to your crops, man the shops, guard the perimeter, enable Supply Lines, and many more. They need bed, Water, and Food. You have to manage these resources to keep up with your workshop's population. You can even assign users to their individual Beds.

You can trade items with generic settlers. This is a good way in changing their equipment, like giving them your surplus weapons or apparel since they'll start off only be equipped with a measly pipe pistol and ordinary clothes. Some settlers may also have bobby pins and bottle caps which they can gladly relinquish to you should you need to. It's a good idea to equip your guards with better armor and weapons so they can deal with threats more effectively. In an event that your workshop is being attacked, a quest will pop up requesting you to defend it. Just fast-travel to that workshop and kill all attackers.

If you have a large area, it will be a pain checking with your settlers so crafting a Bell is necessary to gather them up like a boss you are. Just ring once (or as many times as you want) and all your settlers will gather around you, even the provisioners and their cargo brahmins.

You can also deliberately kill your settlers. However, this will turn the entire settlement against you. The game doesn't have a karma system but this action may affect your relationship with your companions (except Dogmeat). I haven't tried yet if the populace will reset their hostility after a while.

Additionally, if you have a new, freshly acquired settlement, you can MOVE settlers from any of your workshops to live in the new settlement. This is useful when you just want them to populate an area without building a generator + recruitment beacon in that settlement. This is also a good move to address the population problem in any of your main settlements.