In Moors of Ykesha, near the Guk instances, head to ( 683, 147, -861 ) /waypoint 683, 147, -861 and walk through the vine wall through the tunnel.
Note: If you take the druid portal to Moors of Ykesha there is a froglok (Zara Dreamhopper) at the Druid Spire, at the landing zone area that will gate you right to the outside of the zone. This will save you the long run. Once there walk through the vines on the wall and there is a tunnel.
Once you have zoned in, there is a named froglok, Rhee'Gor, which will select hard mode or normal mode. If you wish to begin a hard mode encounter, approach him but do not attack him. He will perform a ritual, which makes the zone much harder. If you kill this named, the zone will be set to normal difficulty.