Swimming Tips

I have an open-ocean, 500 yard swim to complete at the end of May to become qualified to be a Surf Instructor. I have a little over a month to train for this. I am in good shape, but have never swam close to 500 yards! The only swimming I do is recreational in the pool or ocean. I am going to go to the local gym to swim laps and hopefully work my way up. Will it benefit me to stop my strength-training at the gym during this month to focus solely on swimming? I’m not sure how far I can swim right now without stopping, but I bet it might be 50 yards max. I’ll need to get my endurance up asap. Any tips or advice on how to make this possible would be greatly appreciated! Thank you so much.

Im applying for a lifeguard position at my school and I swam for 2 yrs at my high school but I have never heard of front crawl swimming… Is that just regular freestyle ?