Simple. Firstly, use the Add Action selection in the context menu...it is your friend if you get stuck.
This example is on a checkbox change event.
if (this.rawValue == "1") {
this.resolveNode("#subform[2]").presence = "hidden";
}
//my page 2 is called #subform[2]
//if you need to show it again, make the rawValue of the check box 0 and presence to visible. When you uncheck, it becomes visible again