How to try "5 Whys":
1, Set a problem you want to solve.
2, Set a goal you want to archieve by solving the problem.
3, Think why the problem happens (happened).
4, Think why the reason which was found at 3 happens (happened).
5, Repeat "Why" until bottleneck of the problem is clear.
By solving the bottleneck you find can be the first step to solve the problem.