Gravity causes collapse to continue. Grains collide and grow into dust balls. These collide and grow into progressively larger bodies. Planets grow by accretion . Process ended about 4.6 billion years ago.
Fusion begins in core of protostar.
Star blows off outer envelope. Super solar wind carries away remains of nebula. Star is now visible from outside. Perturbations of comets by gas giants in outer planetary system throw some comet nuclei and asteroids into distant orbits about star. Heavy bombardment as planets sweep up asteroids and comets.