Do Guardians of the Galaxy during the day and at night - it’s different.
You probably know, but Pirates is a lot different at Disneyland - much longer. I love New Orleans Square, so spend some time walking around and seeing the details there - it’s a different land than in WDW.
I also love Toontown - the rides aren’t totally great, but I do like Roger Rabbit’s Cartoon Spin, but the details there are fun and amazing too.
Focus first on the things that are different than WDW.
Grand Californian Hotel is a great place to rest and take a break, and it’s so close.
It’s super easy to park hop, so don’t worry about the time, you can go back and forth at will.
I agree with bestsrina2. Enjoy the parts of DL that it are non-existent or much better than WDW. The Old World Bavarian Charm of Fantasyland, New Orleans, Sq., Adventureland, the Matterhorn, Alice in Wonderland, StoryTime Boats, Nemo Submarines, and a better Buss Lightyear. ENJOY!
Yes, it’s easy to use. Once you enter the park, you can make your first max pass, and then it will tell you the time you can make the next one. After your first one, you don’t even need to be in a park to make the next one (on the same day).
I recommend watching a YouTube video on it beforehand. It can help you conceptualize what is happening vs us trying to “tell” you about it. I find it very intuitive. It maybe a little harder for you since you familiar with the FPP system at WDW. The systems are slightly similar, but some aspects that are very different. For example, you cannot select your time, it just gives the next available fp time.
When you get a Fastpass, set your phone alarm for the time when you can get the next one because that information goes away. That way you can stack as many as possible. My other tip would be to have cocktails at Trader Sam’s and the lounge at Carthay Circle.