How can I update from a screen that is call within a report program?

I created a screen to capture new data and save it on the ztables that i created, this screen is part of a report program that works as fallows:

(in a selection screen) if the customer exist will display a basic list with the info. of that customer.

if the customer dosen't exits, then i call the screen to create the customer. i'm stuck in that part. I don't know how to update the ztables from the screen.

can someone help me.

this is on mini sap 6.10

regards....

Fidel Peralta