If you just put those attractions into your plan and tell it how many you plan on using (I tell it 3) then it will arrange the plan and you’ll see recommendations (in blue) under the rides it suggests you use FPP for. I will then enter tentative FPP reservations based on that (I will usually set the TP arrival time to be in the middle of the FP window, unless I have things like other FPs or dining plans that might overlap) and reoptimize without selecting the “force it to use my FP reservations” option. Sometimes that will adjust things enough that you now have better 2nd/3rd FP options, and other times it will just shift things slightly.
Something to note, especially for TP newbies: as fun as it is to plan now (and we pretty much all do it), keep in mind that for the present the TPs are mainly just tools you can use to get an idea of what times to have meals, do FPPs, etc. Quite a lot may change once you actually make your FPP, and in the couple of weeks leading up to your trip but even drastic changes don’t mean that your trip is ruined. People tend to get in the “I have a PLAN” mindset a little early, and then get thrown for a loop and feel slightly (or extremely) panicked when things happen like RD time changes, CL changes, new shows/packages are announced, etc. In other words: try not to get too attached to your TPs until A. you actually have your FPPs booked, and B. just a few days before you leave and even then don’t live or die by the plan… everything might change the day you get there and you’ll still have a wonderful time.