I just got the Local Leader perk, it says I can establish supply lines between workshop settlements. How do I do this?
In order to set up a supply line you need to have the Local Leader perk and a spare settler. Enter Workshop mode and select the spare settler and press the highlighted button for Supply Line:
This provides you with a list of your eligible settlements to set up a supply line with:
All supply lines are visible from the map:
You must have levelled charisma to at least level 6, this can be done by going to perks
Scroll down to level 6, and put one level into local leader. Local leader perk allows you to establish supply lines between your workshops.
Go to any settler from a different settlement while in workshop mode and you will now see a button (Supply Line) available
Pressing the button will prompt a box asking you to select which settlement you want to have the settler travel to.
To check which settlements are linked to each other you can open up your map and press (Show Supply Lines)