Link set is a way of organizing links:
Find and use link sets that others have made.
Try the buttons in the footer for further examples.
Pressing a phone button will activate your phone. You will have to press the call button to call the number.
Pressing a SMS button will activate your messaging program with the selected number(s) filled in.
Pressing a mail button will activate your mail program with the selected mail adress(es) filled in.