Believe me, there is really only 1 way that makes sense to insert a PCIe card into an PCIe Slot,
so that the card fits into the PCIe slot and that you can fasten it with a screw.
Turn it around and around, there is only 1 way that makes sense (no matter what might confuse you in any diagram).
"Upside down" is relative, in some cases cards sit horizontal (Tower), in other cases vertical (Rack).
Whether maybe the 9- or 25-pin connectors in the diagram are flipped 180° or not is completely irrelevant.
It is like it is, you simply need to insert the PCIe card into PCIe slots.
If you are not familiar with this concept, please ask a PC technician if this all still makes no sense to you.
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