I'm unfamilliar with question 1. I've never seen a grounding wire on a modern PSU. I would imagine to look into the instructions and see where to stick it.
For question 2, yes, pretty much. The connectors are all keyed so will give you resistance if inserted incorrectly. You DO have to be mindful of a few though. All motherboards need the ATX connector, most need the 4pin CPU connector, and if your video card needs it, the 6 pin PCI-e connectors.
I’m building my first pc atm and have a few questions about the wiring:
1. How do I know exactly where to put the ground wire from the power supply?
I've also never seen a "ground wire" from a recent computer PS. Please list the model numbers of *all* the components of your system (especially the PS) to give us a better idea of what's really going on here.