If that center nut is a left hand thread, run all your plate back in, take an air gun and get that nut off. Push the plates into themselves as if you are the pressure plate. Use bursts of shots so the clutch won't slip as much, you won't have your fingers chewed as it spins. The bursts of the gun will shock it off. Then, there's the puller tool if there is one.
Relax, you're doing fine.
When you remove shit, lay it out as one long stack so the last part you pulled out, goes in first is think like a parts blowout page laying it out.
Look at the crap coming on the pressure plate. Working outside is not the condition you want to keep something open and exposed to that environment. Shit blows around and heart surgery is not done outside, think.
1. Clutch plates have a cut side when stamped out so look for that (sharp) side. All those cuts face you upon assembly.
2. Each steel rests on a friction so stagger correctly upon assembly.
3. Which one starts and which one ends? Download that pfd to see the parts begin and end. I'm not familiar with the basket, nor are there enough shots so I can see the other side of the clutch pack, and a fanning of the plates out from that plate. I'd take a guess, but think about it. She only goes together one way.