I don't have pictures, but I wondered the same thing a few weeks ago. It is not similar to the ADR system.
From what I remember... when you log in, at 12:01am you will be allowed to choose a day, then choose your party (all or individually). Then you will choose a park, then an attraction. I believe a time filled in automatically, but you could change it. It then chose two more attractions and times for me. The first day I was working on (the last day of my trip) I was most concerned with getting Anna & Elsa, so I let the other two go, then moved on to a different day, again choosing my most important attraction, and letting the other two fill in. Don't close out of a day without picking three things, even if you're not sure about all of them.
The other days I was picking things that I wasn't married to a time frame, and things I knew weren't crazy hard to get like A&E, so I went back to the first day I worked on and chose attractions I wanted with times that fit my loose schedule. Repeat as necessary.
It's been almost 3 weeks, and I've gone back in several times and tweaked my FPs for all the days we will be in MK. The only one I haven't touched is A&E because there is no other time available.
I was anxious that night, but it was easy once I realized what was going on, and that i could go back and tweak things.
