Waiting for return?

Hello. I am created script that requests ModuleScript to show selection window. ModuleScript sending result back with return command and I want to save it to variable but return returns nil. How to make script wait for return?

This is how i am request return.

var = require(something).proceed(something)

ModuleScript showing window and based on user answer returning something. But var is set to nil right after and it's not waiting until ModuleScript return something.