How can I get user inputted information into my code?

I am making a gui with a qwtplot and I want the user to be able to fill in a text box with a file path. When they push enter I want that path to be transfered into my code so that I can load and plot it. I don't even really know where to start, I have been looking through the qt examples but I can't find one that I can work with.

Do I need to make a custom signal/slot function? If so could anyone point me to an example or show me some code syntax on how it would work?

thanks a lot!