Assuming you have an auto trans:
-remove the rubber plug circled in red in the photo
-rotate the crankshaft until a slot appears in the opening
-place a screwdriver in the slot to hold the crank while you tighten the crank bolt
On the same side as noted, but lower down on edge of housing, there is a bolt hole. You can fit a round screwdriver through it, rotate the crank until it slips through the flex plate.
(thanks to Canubaru for this info).
Its on both sides, but access is easy on passenger side.
On BE series and later the hole is still there, but filled with a short 14mm bolt.