King of Avalon almost always has one or two seasonal events being active. At this time the Mardi Gras Event is one of them. This guide explains how the event works.
During the duration of the event you get a chance of receiving Carnival Beads when slaying monsters and rallying Barbarian Camps. These Carnival Beads show up in your items where you can use them to get prizes.
You do not have to do anything else as what you normally have to do anyway to get Carnival Beads, whenever you have Stamina you should kill Monsters or rally Barbarian Camps.
You get your prizes by selecting the Carnival Beads in your items and clicking uses. Prizes I have received include: Gold, 500 Lord EXP, 500 Dragon EXP, 30m VIP, 10 VIP Points, 500 Dragon Spirit EXP, 1k Food, 1K Wood, Knucklebone, Rune Stone, 5m Speed Up and 60m Speed Up.
There is not much to it, just do what you normally do and collect the extra prizes. If you have any questions, or comments, let me know in the comment section.