New Installation - How many SQL user CALs does a user need?

I am joining a company that is beginning a brand new SAP B1 implementation and they (we) are trying to figure out the best way to license SQL server.

We are installing onto a server with a total of 24 cores (48 w/ hyperthreading enabled) but were planning on getting a license for twelve of them.

In a chat with Microsoft, I was told that we would actually need to license every core on the machine - which would obviously double (or quadruple) the cost and make per user licensing more logical. But, I have heard that each real user needs more than one license CAL.

Is that correct?

Is there a reference on how to go about picking license styles between server core and per user?

Any help would be appreciated.

Thanks in advance.