Okay so I have a few questions. I am 19 almost 20, 5'9 and 240 pounds!
What weight should I try to get to? ( healthy weight)
What are good at home work out videos for beginners to lose weight?
When I go to the gym what should I do?
What should I eat?
Help please!!! I googled all these and I can't find anything that is consistent so I don't know what is true and not.

The Biggest Loser Weight Loss Yoga
The biggest Loser Cardio Max (haven't tried it yet)

Try walking at least a mile everyday or every other day.

Just portion control. MyFitnessPal is a calorie counter and it will tell you how many calories a day you need. Just use that to gauge how much you should eat. Lots of veggies, fruits, good proteins

It's not too hard you already have a base knowledge of what you need to do its just a matter of going out and doing it get creative with recipes as well! Get the most of your calories for less!