You should end up in the Dashboard:
ALL IMAGES NEED TO BE EXACTLY 700px wide by 900 px tall!!
Go to the menu on the left and select Media > Add New:
You will be able to select your images for the home page:
Once they’re done loading, go to your Media > Library:
Select all your new images (checkboxes on left):
Click “Attach” on one of the images:
With the Pages option selected, type in Promo and hit “Search“, then select Promo:
Those new images should now be on your promo page!
To delete the old images, just select them all (checkboxes on left), the select the bulk action of “Delete Permanently” at the top: