Unless you have a travel agent you like to use, yes, just go to the universal orlando website and click around.
But....I have never found it to be a savings to get the package; getting tickets and hotel separately has always been to my wallet's benefit. And you get the same advantages by simply staying onsite as you do by booking a package for an onsite hotel (early entrance to wizarding world, the fabulous express pass plus). The ONLY thing I've found as an extra with a package is the *breakfast* at the Three Broomsticks, and when I was looking, it cost just about exactly a breakfast-for-three more for the package as booking a "normal" package with no breakfast. And both of those were more expensive than booking a hotel on my own and buying tickets on my own.
This way you don't have to pay things in advance. There are no penalties for changes and if the room rate drops, you can just call the hotel back and have them adjust.
April is peak time, so I wouldn't expect any discounts. Prices will be very high.
We usually book with a AAA discount for the room and then buy our tickets at our local AAA office with the discount they offer. If you are a AAA member that may be a way to get a discount and you also get discounts at the restaurants and stores. We book directly with Loews and tell them we are AAA members. As pp have stated, we have always found it cheaper to book the hotel and tickets separately.