Hi Susana!
I'm loving the convenience of the My Disney Experience App. If you're going to link tickets, you can easily scan them in using the app, and it just takes seconds, but don't worry, I'll go through the linking process using the My Disney Experience website as well!
Using the app, you'll log in, then up on the top left of the screen you'll tap the three horizontal lines placed close together, this will bring up the menu. From there, you'll scroll down to
Tickets & Passes, and select that option. Then, tap
Link a Ticket or Pass. This will activate the scanner function on your smartphone, and you can scan the ticket in. You'll also have the option to enter the ID Number on the ticket as well. Once scanned, you'll link that particular ticket to a member of your party. The app will walk you through that process fairly easily.
From your desktop: go do
www.mydisneyexperience.com, and log in. Then, you'll select '
connect additional reservations, tickets or friends. This will walk you through the steps to link the tickets. It's very similar to the app process, but you won't be able to scan in the ticket in link you can with your smartphone, you'll be inputting the ID Number from the back of the existing park ticket.
Have a magical vacation!
Amanda