Hello Colleen,
Thanks for stopping by planDisney! Summer is such a fun time to visit Walt Disney World, but the parks do tend to get crowded, so I think you are really going to love having
Disney Genie+ to help you skip the standby lines on a lot of really popular attractions.
You'll be happy to know that, yes, you can absolutely make Genie+ reservations for your arrival day, beginning at 7 AM. Keep in mind that Genie+ times typically show next available, so right at the beginning of the day, you'll most likely see time windows only available before your arrival. The exception to this may be super popular attractions like
Slinky Dog Dash and
Millennium Falcon: Smugglers Run in Disney's Hollywood Studios,
Test Track in EPCOT, or
Jungle Cruise and
Peter Pan's Flight in Magic Kingdom. You'll probably be able to find some times early on in the day with later times available. You'll most likely want to book your first Genie+ Lightning Lane access for sometime after 2 PM to give you time to get to your resort, have something to eat, and get to the park where you've made your reservation. You should be able to book a second Genie+ reservation 2 hours after park opening, even though you will not have used your first yet.
If you want to purchase Individual Lightning Lane access, that is entirely separate from Genie+, and you can do that as well at 7 AM if you are checking in to a Disney Resort Hotel, or at park opening if you are staying outside of Walt Disney World. Individual Lightning Lane purchases are for some of the most popular attractions that aren't included in the Genie+ offerings, like
Star Wars: Rise of the Resistance,
Seven Dwarfs Mine Train, and
Avatar Flight of Passage. Of course you can wait in the standby line for any of these attractions, but you can also pay a fee per ride to gain Lightning Lane access. Unlike Genie+ bookings, you can select your return time window when you make an Individual Lightning Lane purchase.
If you haven't already added the My Disney Experience app to your mobile device, I recommend doing that right away. That way you can get familiar with checking the Tip Board for each park, seeing the wait times listed, and what Lightning Lane access is available.
Hope this helps. Have a magical vacation!
Diane