Hi Sue,
Coming to Walt Disney World for the first time can be overwhelming, and we on the Disney Parks Moms Panel are here to help you understand it all!
You can purchase Base Tickets for the Walt Disney World theme parks. These are Magic Kingdom, Epcot, Disney's Hollywood Studios, and Disney's Animal Kingdom. The
website for purchasing Walt Disney World tickets will help to guide you through this. If you are purchasing a one-day ticket, you will need to specify if you want it for Magic Kingdom or for one of the other three theme parks. Multi-day tickets will work at all four theme parks. If you purchase four-day tickets, you could spend all four days at Magic Kingdom, or one day at each park, or any combination thereof; however, you can only visit one park per day. If you add the Park Hopper option, this will allow you to visit more than one theme park per day.
To your theme park tickets, you can add the Water Park Fun & More option, which will add "fun" visits to your tickets. These include Disney's two water parks (Blizzard Beach and Typhoon Lagoon), ESPN Wide World of Sports, DisneyQuest, and Oak Trail Golf Course. The number of "fun" visits you get is the same as the number of days for which you purchase tickets - so if you buy four days of tickets, you get four fun visits. These venues would require separate admission if you do not add them to your theme park tickets. Other special events also require tickets. These include Mickey's Not-So-Scary Halloween Party, Mickey's Very Merry Christmas Party, and Night of Joy.
I hope that this information helps you get started in planning your Walt Disney World vacation, Sue. I would love to help you more; however, I am limited in the amount of space I have to answer. Please do let me know if you have any further questions!