So General Grievous will be on the Providence Class Destroyer

He will also have his army:

1,238,000 B1 Battle Droids

250,00 B2 Super Battle Droids

10,000 Droidekas

2,000 Commando Droids

8 C-9979 Landing Craft

160 MTTs

120 Vulture Droids

120 Droid Tri-fighters

This will be during the time when Grievous captured the Palpatine.

Update will be soon