It takes a while to get fuel from the tank up to the fuel pump from a bone dry tank, sender and fuel lines.

All my stuff was also brand new, so before I started cranking my engine after getting it all together, I put a hand vaccum pump on the fuel line from the tank up where it connects to the fuel pump and pulled fuel from the tank so I would not be cranking for quite a while.

Once you make sure you have fuel to the fuel pump and then you find out you still have no fuel coming up to the carb - then you might have a fuel pump problem.