What did the Eighteenth Amendment prohibit?

Prohibition of Intoxicating Liquors

It actually prohibited the manufacture, sale, and transportation of alcohol but not the consumption.

Judy is right. It was not illegal to drink alcohol under the 18th Amendment, and many private clubs merely bought huge supplies (while it was still legal to do so) to serve their members, using membership dues to absorb the costs.

The 18th Amendment
Section 1. After one year from the ratification of this article the manufacture, sale, or transportation of intoxicating liquors within, the importation thereof into, or the exportation thereof from the United States and all territory subject to the jurisdiction thereof for beverage purposes is hereby prohibited.

Sections 2 and 3 deals with enforcement and ratification.

Now you tell me! Wish I had known that back then!