I'm not too knowledgeable about bikes, first of all. I have a road bike and I'm pretty sure it's a ten speed (it has 5 gears in the back, and then two big gears towards the front). Anyway, the other night while I was riding, my chain came off, so I had to put it back on. Maybe I didn't put it on the right gear because it came off earlier today. It just happens like every 1/3 times I ride it. The bike is an older one with the gear shifter that doesn't automatically set (like, there's no 1,2,3...10). It's like a little lever (2 levers, one for the front, one for the back). Can you tell me how to set my gears to be normal. Like when the left levers forward, where should the chain be, and same for right lever. Thanks!