From the main menu, go to "Lasagna Challenge", then set the difficulty to easy and play against 3 bots. Or, if you want to make it even easier, you can connect up to 4 controllers to give yourself an even better chance. This isn't necessary really though, as all challenges are pretty easy to win.
For this one you need to be the last one standing on the iceberg. You can charge at people with
, but this is more dangerous than it is worth. Just avoid everyone and you should get an easy win. This one takes place over 3 rounds, so don't worry if you screw up the first round.