Naming hydrocarbons

-OH has a higher priority.

Start the carbon numbering either from the left or right.
Choose the direction such that the most significant functional group will have the lowest possible carbon number.

butan-3-en-1-ol

butan-2-en-1-ol

butan-3-en-2-ol

Note that for branched chains, the direction is not just "left" or "right"

alcohol.
so it can't be "hydrocarbon", right?