Hi Tracy
There's nothing to worry about with a connecting flight. You'll check in at Manchester and board the flight to JFK. At JFK, your bags will be transferred to your next flight for you, unless you are told otherwise. Then you just have to look for your departure gate for the flight to San Francisco, just as you looked for the JFK gate back at Manchester.
You may find there's a bit of spare time at JFK. If so, you might want to have a drink or something to eat or maybe do a bit of shopping. Just make sure you don't leave the airport!
I'm sure you'll have a lovely trip with us - the Golden West tour is always a big hit.
Kind regards,
Olly, your editor