Okay. If you haven't, draw a Free Body Diagram (FBD). It might help you to visualize what is going on.
Good start solving for the max static friction. Think about where the force comes from. What is F in it's most basic form (Think of Newton's Laws)? Once you have that, look at the FBD and see what you know and what you don't know.
If you're still having troubles then, let us know where you get stuck and we'll see what we can do to assist.