For C-Points. It's no where to be found. I see character slots but no foundry slots. Do you have to meet certain requirements to unlock the ability to buy Foundry Slots or is there something else I'm missing?

It's in-game, provided you have either unlocked foundry as a silver player or are a gold member.
See Here.

Uh yeah...my question is how do you unlock the Foundry as a Silver Player? I thought you buy the slots in the C-Store but they're not in there.

at the character selection screen, click on the create content tab. There should be a clickable button on the lower section of that page stating you can purchase foundry slots.

The cost is 10k Dilithium for a 'starter' pack of 4
after that you can buy 2 slots for 7k or another 4 for 10k
I believe the max # you can have is 48


Be advised, there are apparently some individuals for which purchasing slot is not functioning properly