Need help adding a transfer switch

Funny, I had it setup with no transfer switch but decided to change it. This whole setup is in my wife's pet grooming trailer and I just didn't want her to have to mess with a bunch of cords and connections. It looks so much cleaner with the transfer switch and everything is handled automatically. Since I've already purchased and installed the transfer switch, I think I'll probably just keep it. But, you guys have been a huge help! I think I'm headed in the right direction now. I was playing with it yesterday and I'm pretty sure it's setup wrong because If I try and pull more than 15A on one power leg, it trips only 1 breaker on the generator and I loose all power. I'll need to get behind the control panel on the generator and change it to the 2 wire setup so that doesn't happen anymore.