Everyone who achieves success in a great venture, solves each problem as they came to it. They helped themselves. And they were helped through powers known and unknown to them at the time they set out on their voyage. They keep going regardless of the obstacles they met.

This quote means that when someone succeeds in a difficult undertaking, they will face many problems along the way. They need to try to solve these problems on their own. Even if they don’t know how to, they should keep going and not give up. People and forces that are not obvious right away may also come to their aid, giving them the strength to keep going and eventually succeed.