maxima overheating dont kno what to do

ive changed the radiator, water pump, and thermostat. i dont know what else to do so if anyone could help me out i,d appreciate it. i ran a diagnostics and some of the things that came up were knock sensor, heater sensor. oxygen sensor, and system idle control. it's my first car and i dont have enough money to fix everything so i wana fix the overheating thing first. thanx in advance
p.s. its a 96 maxima gle

Bleeding air bubbles is most important and has to be properly done after fillup or you risk blowing heads. Check this page: engine is older but the issues are same and by clicking on links youll find all u need for your engine http://www.cardomain.com/ride/748507/8