I just replaced all my brakes on Friday. Unlike auto brakes, the calipers are easy to "retract" by just pushing them. This will give you more room to insert your break pads. I know that this does not pertain directly to your issue, but if you have only widened the calipers then by applying the breaks they will close back down on your brake rotor.
On the back brake there is a small rubber cap that covers the bolt holding the brakes on and on the front there is no cap. Just unscrew the bolt and you will have to apply some pressure on the pads as there is a spring on the rear of the caliper that is applying constant force.
So. for your issue. Sounds to me that you have not gotten the back of the pads completely set in the "springs". I found that when putting in the "outside" brake pad do it from the same side of the wheel as the pad, but then putting in the "inner" pad do it from the other side of the wheel. that way you can see the back of the pad and if it is in the "spring". I would suggest that you just remove the bold that holds on the pads as it will make the assembly much easier.
Michael