Sharon,
We used to have a replacement schedule for this on the updates page, but now that we've updated our Little Hands to Heaven guide to include that schedule it's no longer on the updates page. Once we put an update in a guide, we remove it from the updates page in order to keep confusion about needed updates for the current edition of the guide to a minimum.
In order to use Big Thoughts, simply do as krismoose suggested. Then, on review weeks, select one of the 4 readings from the previous 4 weeks to review (or you could instead review all 4 of the previous 4 week's verses).
Blessings,
Carrie