1) check your DVR manual on what is the max HDD supported (ie some DVR only support up to 2TB so connecting a 4TB will not show in the DVR)
2) also check your manual or website of the manufacturer on which HDD is compatible. some DVR will not detect a seagate HDD or a WD HDD.
3)you don't need to format the HDD in the PC, you format it inside the DVR. most DVR uses a variant of Linux.