According to the instructions in your referenced post (without digging too much into the overall process), you don't put anything there in the first "Assign Token Values" task. In that task, you're just creating the token and leaving it blank.

Then, later in the process, in the "Assign Token Values 2" task, that's where you're adding a value to the token using the For Each loop iteration:

Assign Token Values 2 - Append the page number that will be deleted to the token created in step 1.   The page number is the iteration of the 'For Each Text Page' loop. %(ForEachTextPage_Iteration)

As far as token tags go, they help to categorize the tokens by type which can control the formatting of values placed there, and evaluate the values properly in conditions. However, I don't see any value in tagging the token here specifically for Page Numbers (I'd just leave it as a "String" type token).