I am pretty much a novice when it comes to working on bikes. I am pretty handy at mechanical things, but have not tackled bikes much. That being said, I just bought an old Peugeot 21 speed from a thrift shop. It is in very good shape except the front derailer. It is stuck in the lowest ring and I cannot get the chain to stay on the second ring when I shift. I have tried adjust the screws on the deraile, but I an doing nothing to get the derailer to shift and stay. Any help here?