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For Walk on the Wildy Side I, you need to complete one of the thirteen Wilderness Flash Event. The Wilderness Flash Events take place on the hour, every hour, throughout each day. Some are gathering events, some are combat, and there are also three 'special' events. There is an announcement in chat 5 minutes before the hour to let you know what the next event is and where you can find it.
At each event there are two goals to achieve in order to complete it and obtain the rewards. One is your personal goal - X number of items gathered and handed in to the NPC at the event, or X amount of damage done in combat. The other is the group goal and scales with how many players are in attendance at the event
The Wiki has a great guide that includes a schedule of which event is up next, as well as descriptions of each event and map locations of where to find them.