Write a method that takes a single integer parameter and which prints that number of stars.
Test it, fix it, make sure it works for every value it might be given.
When it does, call it inside a loop with alternating numbers: 4, then 3, then 4 again, and so on.
If you are having problems getting started at all, then this may help:
How to Write Code to Solve a Problem, A Beginner's Guide[
^]