How do I format a phone number in a number field?

How do I format a phone number in a number field?

Ugh!!!  I've read all the post on formatting a phone number but I'm confused.  Is there anyone out there who could provide baby steps on how to do this in Zoho Creator?  I've looked for videos but can't find anything.  Even screenshots of each steps would be so helpful.  I've read all the tutorials and none of them make any sense.

Please help,

Lisa