if the starter solenoid isn't engaging, then is the relay engaging under the hood? this will let you know which direction to go in.
if the relay is clicking, then you might try changing relays around to make sure it's good. if you're horn works, use the horn one, but change it around.
if still relay clicks and no starter, then probably something in the starter or wiring to starter.
if no relay, then there is a bunch. but start there.
of course as peva starts, make sure the battery is good and connections good.