Be careful not to confuse postpositions with the separated prefix of a separable verb! When such prefixes are placed at the end of the clause, they can look a lot like postpositions:
Lesen Sie bitte die Anleitung gründlich durch.
Please read the instructions thoroughly.
Kinder, zieht euch einen Pulli über, es ist kalt draußen.
Kids, put on a sweater, it’s cold outside.
You tell whether it’s actually a postposition, and not a separable prefix, by looking at the noun phrase together with the postposition. Does it make sense? Then it’s a postposition!
die ganze Nacht durch
the whole night through
einen Pulli über
a sweater over