[SUBSTR|startCharacterNumber|numberOfCharacters|textToGetSubstringFrom] - get a sub string from "textToGetSubstringFrom" starting at character "startCharacterNumber" (integer, 0 is the first char) with a length of "numberOfCharacters" (integer)
1. [SUBSTR|0|4|[GUESTPHONENUM]]
This will test for the first 4 characters of the Guest phone number.
[TRIM| string to trim ] - remove whitespace from the start and end of " string to trim "