Harvest Help for First Time Grower

I have the following herbs: basil, parsley, dill and cilantro. I have no idea when to harvest, what part of the herb do I harvest and what do I do? Dry it? How much do I cut off? What about bringing indoors once the end of the season comes or leaving outdoors what to do to protect the plants? Would I cut the plants down? Cover with straw?

For all four herbs you can harvest leaves and use them fresh. You can cut leaves anytime, and chop fresh as much as you need into foods. Anything with tomatoes goes well with basil, cooked vegetables such as carrots and potatoes go well with fresh chopped parsley, dillweed on fish or cucumber dishes is heavenly, and cilantro in savoury salads and soups and stews. Just chop 'em up and sprinkle over.
You can harvest leaves for fresh use anytime through the summer and fall. For drying, it is best to wait until herbs begin to flower – that's when tradition has it that herbs have the greatest flavour, and that also happens to be when they have their greatest size. Generally, the herbs are cut down low enough to remove most of the leaves.
Although it is theoretically possible to dry parsley, dill and cilantro, it is hard to preserve the flavours, and most people don't bother. Basil dries well, and you are encouraged to try.
We have answered questions previously on drying and posted our answers in the "Q&A" area of our website. I encourage you to look for them because we go into drying in more detail. Briefly, the challenge is to dry quickly but not too quickly or you will lose the flavours.
None of the four herbs are perennial. They will not come back next year; you will have to replant in spring.