Summarizing/adding to previous specific answers:
Why did the protoplanetary disk start rotating around the star?
The disc forms because it was rotating. Without net rotation it wouldn’t form a disc... it will bestay a spherical symmetric cloud.
Where did the initial energy to rotate come from?
A small angular momentum NOT energy is required the “angular energy” gets magnified during gravitational infall while conserving angular momentum like the figure skater spins faster pulling arms in with small initial rotation.
Why hasn't all the disk material been swallowed by the star?
As it speeds up it is basically orbiting faster and faster until centrifugal force balances gravity. Equilibrium.