Newbie confused

I want to use certificates to monitor windows Exchange DMZ servers using SCOM (Microsoft OpsMgr).
I have no idea how to start, or even what question to even ask about how to buy the correct certificates.
Can someone pls point me to a thread that has this info? Or let me know what I need to supply as info in order to buy the correct certificates?
Thankyou very much, ???
John Bradshaw

This link might help.

Or maybe a call.

good luck.