antifreeze shooting outs reserve when car overheating in 97 malibu

[malibusmostwanted]

i had intake gasket fixed but my wife came home for a couple minutes on her lunch break and we went to luch but a couple of mile the car started overheating....we pulled over and popped the hood...there anti free was blowin outa reserve and steaming...it wasn't leaking from anywhere else...i filled back up with antifreeze so we can get it home since we were very close it start to overheat again as we pulled into driveway....i mean it overheated till light came on....the heater stopped working and so did the fans prior to this same day....i was told either fuse or thermostat....fuses are good but i dont know enough about cars to find the thermostat...i heard there very easy to change...any suggestions on what problem can be or how to change thermostat to see if thats it?

[GMMerlin]

How long was it from the time you had the intake leak repaired and the overheating problem started?
if it was recently, there is the possibility of an air pocket in the cooling system...this will cause what you are describing