Welcome to planDisney, Renee!
I'm so glad you held on to your
ticket that you purchased prior to the closure! The magic has certainly returned to the parks and many wonderful memories await you! In order to
make theme park reservations, you will first need to link the tickets to your Disneyland Resort account. You can do this using the Disneyland app or by clicking the "Link Tickets" link under the "My Disneyland" menu on the Disneyland Resort website.
Once your tickets are linked, you will want to check the
theme park reservation availability calendar before making any plans. Additionally, if you have a one-day ticket from before the pandemic began, it's likely that the ticket is in a designated tier--Value, Regular, or Peak. Depending on the tier your ticket belongs to, there are certain days you will not be able to use your ticket at the parks. This
FAQ outlines which dates are blocked out for each ticket type.
After you have confirmed your dates are good to go, go ahead and make your theme park reservations for each day you want to visit. If you purchased Park Hopper tickets, you will make a reservation for the park you want to start at each day and then at 1:00 p.m., you may hop to the other park.
I hope this information was helpful. Have a delightful time at the Happiest Place on Earth!
-Linda