I don’t want to teach anything to anyone, but if you find something interesting here, feel free to use it.
I treated it not like a saga-movie but like a spinoff, using different text.
-Introduce Dooku: I don’t think you need this. He is the bad guy, you can explain it with Palpy at the beginning of III, when he says “He is a sith lord”.
-Explain the Clone Wars: some flashbacks, or text.
-Introduce Padme: yeah, this is needed.
Of course you have to decide wether to use mostly ROTS, or if you want to show different parts of the prequels and place time-jumps during the movie…