Choose products from a specific collection in the drop-down menu, or scroll down to see all your saved products to click one by one.
Highlight Copy if you want to keep the product(s) in the current collection + move to a different collection. You can choose the collection in the drop-down menu or create a new collection.
Highlight Move if you want to move the product(s) to a different collection altogether. Keep in mind, this will remove the product(s) from the original collection you chose.
Also, you can rename collections at any time.