Script [5.3.1]:
set firstName to "Nayan"
set lastName to "Seth"
set myName to firstName & " " & lastName
display dialog myName
Explanation: Variable firstName will store Nayan and variable lastName will store Seth. Variable myName will store Nayan + space + Seth that is Nayan Seth. And a dialog will pop up displaying myName.
Figure 5.3.1 Output of Merged Strings