Help with Phone Call

Hey guys, I'm back. I have a question regarding forward a phone call to a number. The  PBX number are as follows 0317126380,3,*71. 

After the PBX number, I want to add random phone number that the customer chooses.

How can I do this, can I use variables or something?

yes, of course

first do the tutorials http://appinventor.mit.edu/explore/ai2/tutorials.htmlto learn the basics of App Inventor, then try something and follow the

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