Attend a hoedown and take note of the different moves people perform. Seeing the moves in person makes them easier to understand than reading descriptions alone.
Recruit a dancing partner. Many hoedown dances are partner dances, requiring you to pair up with someone. Taking a partner to the hoedown makes you more prepared.
Take a lesson in basic square dancing and contra dancing. Square dances are dances in which couples switch partners while dancing with one another, while contra dances rely on lines of dancers that face their partners. Taking a lesson helps you learn the basic moves that you need to know, so when the caller announces them, you know what to do.
Contact the hoedown coordinator to see if the caller has any dances prepared. You may be able to procure an advance copy of the choreography so you can practice ahead of time and brush up on any techniques with which you are not familiar.
Go to the hoedown with your partner and join other dancers on the dance floor. Listen carefully to the caller so that you can follow along with his or her moves -- if you are unsure of what to do, watch the other couples around you and follow along.