tired of being so big!

Sela

starting this weekend I want to sign up for the gym again and start working out. the last time I weighed myself I was almost 240lbs. I usually just work out at my house but I always lose motivation and stop. I'm going to the Bahamas the first weekend of October and I want to see how much weight I can lose by then. can anyone tell me the main machines, or anything to focus on while at the gym? please and thank you!!!