There's no triggers for waygates. Instead, you make buildings with the "Waygate" ability (such as the normal Waygates have). Then place your Waygate down in the map somewhere, and double-click it. In one of the tabs (I forget which) it has the option for which region to teleport people to. So make a Region (you should know how to do this) somewhere, and select that region in the waygate. Voila. Just duplicate this going the opposite direction for a 2-way gate.