im pretty sure your thermostat is gone. First buy the part. Probably costs $7.50. Also buy a thermostat gasket ($1.10) and gasket sealant ($7)
Find the upper radiator hose, untighten it from the thermostat housing (aka "waterneck"). This will be in front of your engine. As long as you follow the radiator hose, you cant miss it.
Next, unbolt the waterneck. Pop it off (w a screwdriver if need be) Below that should be your thermostat. Yank it out. Clean the area. Place in the new one, throw on the gasket w. some gasket sealant.
The first time you do it might take 30-40 minutes. If you've done it more than twice, then it's a 10 minute job.
if not then check all fuses and relays. and if those are good you may have a potential bad head gasket. check oil dipstick if there is water mixed in it.
good luck