Do not click the gate right by you after zoning, it is the exit
Speak to Sira Cogtree on a ledge next to bottom of the waterfall ( 78, -8, 158 ) /waypoint 78, -8, 158
Return to the Workshop's basement and speak to Jarith. You can use the gate where you entered ( 104, 57, 52 ) /waypoint 104, 57, 52 to return to Frostfell Wonderland Village, then zone back into the Frostfell Workshop
This article refers to events, personae and activities only present in-game during the annual Frostfell celebration. Frostfell comes to Norrath each year from (roughly) the second week of December to the first week of January.