While you're not told directly what to do, your Quest Log will indicate your objectives. Holding down Alt to keep the points of interest highlighted makes this much easier. When carrying the kegs you do not need to target the stand after picking up a keg. The keg will automatically drop from you when you get close enough to the stand. The slalom flags are very sensitive. Even after you have passed one, if you stumble back onto the wrong side of it, you will be disqualified. Fortunately, there is no entry fee and no penalty for failure, so you can try repeatedly.