This example puts the string "Hello" on every row of the screen.
Sub Main()
Dim Sys As Object, Sess As Object, MyScreen As Object
Set Sys = CreateObject("EXTRA.System")
' Assumes an open session
Set Sess = Sys.ActiveSession
Set MyScreen = Sess.Screen
For i = 1 to MyScreen.Rows
Hello$ = " Hello "
MyScreen.PutString Hello$,i,1
Next
End Sub