Question about Celtic Cross Spread

Hello Everyone,
I have been reading and studying The Ultimate Guide to Tarot by Liz Dean. I am confused about a part where it explains how to do a present, past, and future layout with the celtic cross layout. Do you choose more new cards for this, laying them on top of card 5 and 6, or do you choose 2 cards from the existing cards in the celtic cross layout you have made? If the latter, would you then add more new cards where you removed the 2 cards? Hope my questions are clear!
Thank you,
Mabel

The CC already has a Past present and future aspect to it. The three cards as they appear from left to right are the Past present and future. So cards 1 and 2 are the present situation. card 5 ( as I do it - left hand of the cross) is the past and card 6 ( right hand card of the cross) is the near future.

Angelika,
Thank you for responding! Looks like I did not see the forest for the trees! I have reread again the part in question and it looks like she suggests to add 1 new additional past and future card to the ones already there and that and where you take them from was confusing me. I guess you get more insight that way. To me, a visual learner, I got confused on the wording.
Thank you for taking the time to help me.
Mabel