Question

What does it mean there's more than one way to cross a bridge

Answer 1

It means there us more than one way to gwt to the other side or solve the problem

Answer 2

It probably means there's more than one way to solve a problem.
A bridge is a problem right? An obstacle you have to cross to reach your destination.
So it's saying there's more than way to bypass the obstacle to reach your goal; there's more than one way to do things.