Hi there, Marie! 
Thanks so much for stopping by 
planDisney and asking us a question about your upcoming visit to the 
Disneyland Resort. A trip to the Happiest Place on Earth with friends sounds like so much fun…your kiddo is super lucky to have a parent like you! 
It’s a great idea to link the 
theme park tickets for your whole group to your 
Disneyland mobile app if you plan to be in charge of making the 
Lightning Lane Multi Pass (formerly called Disney Genie+) selections for you all. If you have already purchased tickets and are ready to link them to your app, the process only takes a few moments! After launching the app, tap the three stacked lines near the bottom right of the screen, and then select the “My Tickets & Passes” section. Tap the “+” symbol in the upper right corner and use the “Link Tickets & Passes” button to add a ticket. Lastly, either scan the ticket barcode with your smartphone’s camera or manually type the ID numbers for the ticket. This process can be repeated until you’ve linked a ticket for every member of your party. You'll be able to make your first Lightning Lane selection as soon as you all have entered 
Disneyland Park or 
Disney California Adventure Park!
I hope these instructions are helpful, Marie. Please feel free to reach out with any other last-minute questions you may have about managing your tickets and Lightning Lane passes before your trip begins!
Wishing you magic,
Courtney