Also, when I got to format the individual card, it says the capacity is only 14.6 GB and what do I set as the Allocation Unit Size or Volume Label?
a) Memory labels assume that 1000kb = 1Mb. This is incorrect: as far as the computer is concerned, 1028kb = 1Mb. Hence, the "useable" memory will be quite a bit less than what's on the box. It's a bit of a scam, but it's also industry standard.
b) Allocation Unit Size is how much memory you want formatted. Spoiler alert: you want all of it, so put 14.7Gb in the box and it should round down.
c) Volume Label is the name of the drive. For example "OS" or "Hard Drive" is the volume label common with laptops that ship with Windows 7. It should be fairly irrelevant what you put down there since it'll be overwritten by the PSP.