do I need to do to keep it looking good Will it continue to bloom all summer? Do I cut them back or just let them go?

Both. Don't you love those straight answers! You need to leave some of the annuals alone so they set seed for next year. The trick is to leave the later blooming flowers and tidy up the early blooming annuals. However, we may have trouble determining who's going to bloom again, so I try to leave some at all times. I doubt you have any perennials flowering if this is a new planting, but those you can leave or harvest the old flowers at your pleasure. Some are so appreciative of you taking off the early flowers that they will flower again.

Congratulations on your wildflowers!

Water once a week (If no rain) and let them go!