I'll give you a brief scenario - I was doing an internship a few summers ago and needed cheap housing. I ended up renting a room from a couple who had an aggressive and dominant 2 year old gelding, and they wanted me to gentle him in exchange for living expenses. When I tried to send him away from me, he turned around and started backing and kicking at me. I ended up putting on 2 heavy jackets, a helmet, steel toed boots, and I went out there and didn't quit till he submitted to me. I won, unscathed thankfully, and after 2 months of hard work he was ready to start under saddle.
Point goes to show that you can't lose against a horse. My very first horse was a spoiled yearling. I had been riding for about 12 years by that point, and figured I would enjoy the challenge. During the first year he reared up and pawed me in the chest,and he also bit me so hard he ripped my shirt completely open. It wasn't until I got a trainer to come out and give me training lessons that I learned how I was allowing my horse to be dominant and what I should do to have a safe and rewarding relationship with him.
Novices always ignore the "get a trainer" advice, so I figured I'd give you a real scenario.
My dear friend who has ridden show jumpers for 15 years and jumps 5 feet and shows 3rd level dressage can't train a horse to save her life, but she can ride like hell. The point is, training a horse is completely different than riding one.
If I were you, get a trainer to give you tasks each week and take a lesson where she comes out and shows you what to do and then you work on that each week. I did that for a few months and it made a WORLD of difference, I learned how to be the dominant figure as well as how to start a horse under saddle.
If you have problems affording a trainer (which you shouldn't if you just bought 2 horses) go work at a horse rescue on your time off. I did that for a few years while working with my trainer and I learned quickly how to work with many different types of horses and got to train some as well. That will help you learn quicker than just training lessons alone.
Anyway good luck, everyone's going to tell you to get a trainer, which is what you should do. :)