Ummm not sure whats going on, but my settlers will come together and stop what they are doing or when I assign someone they just stand there and no matter how many times I assign them it's the same effect. It's kinda spooky and anoying

Also wanted to ask if assigned do settlers auto harvest what they are assigned to? if so in what frequency.

This is on the xbox one so you know.

Go in to Workshop, highlight Settler. Anything they are assigned to will also highlight.

When you assign, hit A to select the Settler, then A on what you want them to do. Wait a few seconds until you see the message 'This resource has been assigned'.

One Settler will tend up to 12 plants or 3 Guard Posts if they're near each other.

Make sure there are clear paths to and around your plants.

Set your farms up in patches of 12 (.5 food plants, Mutfruit counts as 1.0) so you only need to assign one Settler to each and they get everything in that patch.

If all that is in order, sometimes they'll just stand around. They'll get back to work eventually.

Note that new Settlers will automatically take up open farming and guard posts, so be sure to mark the ones you've assigned somehow - like a certain hat - that way you can spot new guys and know that no hat = no job.