When you purchase a Photo Set from a Creator, you should first check if the file is already attached to the store listing. If so, you will be able to download the Photo Set in the form of a .zip file directly from your Purchase History (found in your drop-down menu). To check if the file is attached, go to the store item listing and look for "Downloadable file" just above the total cost.
If the file is attached, go to your Purchase History, locate the purchase, click the 3-dots to the right of the item and click "Download" to receive your purchase.
If the file is not attached to the item listing, the Creator will need to send the Photo Set to you by some other method. The Creator will have 30 days to fulfill the order before it is considered overdue and you can private message the Creator within that period to discuss your purchase.
If the order is not fulfilled within that time frame, click here for more information on undelivered store items.