The Array tag will create array1 from single value Parameter tags (Rp, Cp, etc).
array1: a1a2a3

The Cpa tag (constant parameter array) will create array2 from constant values.
array2: b1b2b3

These were displayed by a Ap tag (array parameter). Ap is similar to Rp (request parameter) but it returns multiple parameter values in an Array.

A Tokens tag can be used to concat values from Parameter and ArrayParameter tags into a single String. In this example a comma is used as a delimiter and inserted between tokens: a1, a2, a3, b1, b2, b3

A Tokens tag can also be used to separate a single String into tokens and store them under new names. We can separate a single Parameter value like "a,b,c" into separate values and store them as Parameter x Parameter y and Parameter z.

x: a y: b z: c

This is useful when you have a webform that encodes two fields of information into a single parameter and you need to separate them on the server. The form element select can only send one option value so you may want to encode multiple fields of information into each option and then use a Tokens tag on the server to separate them.

Source