In terms of driving in the UK and getting a licence, once you move to the UK on a visa, you can legally drive on your US licence for 12 months.
If you want to continue driving after those 12 months are up, you will need a full UK driving licence - which means taking and passing all the UK driving tests (theory and practical).
You will need to apply for a provisional UK licence in order to take the tests, but if you can work on getting your licence before the 12 months are up, you can continue to drive as normal on your US licence.
However, if you haven't passed the UK tests and got a UK licence by the end of the 12 months, you will be treated as a learner driver - which means: you cannot drive alone, you must be accompanied in the car at all times by someone over 21 who has held a full UK licence for at least 3 years; you will have to display 'L' plates on the car and you will not be allowed to drive on motorways.
It can take a few months to pass the UK tests, and it's a good idea to take a few lessons to learn how to pass the test, so I'd get started on it soon after you arrive.
In terms of getting insurance, I think people here on the forum have had luck finding insurers who will take into account their US driving history.