Once your get your passport back you will get a confirmation document (COPR). You take both passport, COPR and a recent bank statement to either some sort of CIC office (not heard of anyone doing this) or just go into the US and back, on the return back, you get a few final questions and your COPR stamped and they arrange to send you PR card. This takes 2-4 months (from what I've read), don't leave the country during this time as until you get PR card you can only enter via a land crossing or private boat.
You can also cross on the return from any other trip abroad if doing one before your COPR expires. COPR normally expires about a year from your medical.
One you have landed you can get new SIN. Good question on the OHIP, not sure if you should renew soon or just before it expires.
I was strongly advised to actually cross into the US and not flagpole. Appreciate that is more difficult if you require a visa to enter the US.
I'm at the COPR received / waiting to land stage as I have a trip abroad in < 2 months.