I've posted a lot here and over at the LF forum on tray developing. A quick search on my name and "tray developing" should get you way more than you wanted to know .)
One piece of advice that I received over 40 years ago when I started tray developing sheet film was to use a tray one size larger than the film size being processed. If it matters, I've always used the "shuffle method."
Do yourself a favor and buy some 4x5 foma film .
the point here is to get the feel of tray processing.
I would learn with the lights on and off with previously exposed film...PRACTICE!!!
make sure you use a pre bath of water making sure the sheets don't stick together!
once you get it...you got it forever!!