Hiya Nicola!
Welcome to planDisney! I hope you are almost done getting ready for your big journey to the United States in a few weeks!
When you arrive in sunny Anaheim, California, you can head to the Main Entrance Ticket Booth found in the Esplanade between the entrances to
Disneyland Park and
Disney California Adventure Park and purchase your tickets to the Parks for that day or your whole visit. The ticket booths tend to be open at least one hour before the parks open and till one-hour past closing. If you visit at 5 PM there will be plenty of time to get those tickets as Disneyland Park is set to close at 11:00 PM and Disney California Adventure Park will close at 10:00 PM. I just wanted you to know though that if you planned to visit the Parks that same day you will find no discounted or "half-day" ticket options. The Park tickets cost the same whether you are visiting for a few hours or the full day. Once you purchase your tickets make sure you make your
theme park reservations right away. You cannot enter the Park without the reservation set up. It is a bit risky as reservations do run out and there is a chance a Park you may want to visit has no availability. If for some reason there is only availability at one Park but you want to enjoy the other one then consider purchasing a ticket with the Park Hopper option. It will allow you to visit more than one Park in a day after 11:00 AM. You can then go back and forth if you like as the day progresses and since the two Parks are so close to each other it makes it very easy.
Make sure to download the Disneyland App when you arrive as it will be of great help in navigating around the Parks. There are helpful tips and also ways to buy the tickets as well if you want to stay in your room and rest when you arrive. Just know that this App may not be available to download or function as it should till you arrive in the United States.
I hope that this helps and if you have any questions please feel free to let me know!
Happy Planning!
-Nimmy