New member in Las Vegas with a 89 Mazda B2200

Remove the thermostat (replace thermostat housing, fill with water) and flush the cooling system with flush product of choice, then flush until water runs clear. Put in new thermostat and coolant. Be sure the radiator is not clogged with tumbleweed and such (bugs other debris).
Timing belt would be good on principal, walking in that heat is no fun.
Check that the thermostatic fan clutch is engaging.