Hi Shan

Tokens are independent of each other so updating one has no affect on the others.

Modifing a Token is simply allowing you to update a previously existing token.

A practice that I typically use is at the top of my Workflow, I create an Assign Token Values (and Name it WF Tokens), and create my initial tokens there, setting each to Single or Multi-Vaue as required.

Then further in my Workflow I may choose to "Modify" those values using the Assign Token Values Modify. In the case of a Single Value, it simply changes the value, and in the case of Multi-Values it will add a Value to the Token. A Multi-Value Token is indexed so each value in the Token has a position (1,2,3 etc). You can also call a specific value from a position using the Token Index feature  (Right Click on the token and choose Token Editor).

In yout image you show above, you have Order Table - Product Description appearing 3 times.

The logic in Workflow runs top down, so it is first creating the Token and then Appending 2 blank values to the same value each time the workflow passes this step, which basically removes what was created previously when the Token is created new.

I would suggest you separate the Create Tokens from the Modify step as I explained above and then just Modify them at this step of the workflow

Hope this helps