Hi Maria, this one is easy peasy lemon squeezy There's two ways:
When you create your listing, right down at the bottom is a blue button, labeled 'Schedule', or
from your Saved Listings page, at the top of the list is a similar button. With this one, you can actually schedule a batch of listings to be scheduled all at once, or with timed increments between each listing.
Hope this helps, let us know if you are still stuck.