Undo bottom coolant hose and drain the coolant.
Put hose back with a new clip.
Open bleed valve on radiator (top driver's side).
Remove bleed screw on hose to heater.
Remove a small hose from thermostat housing.
Fill system with clean water until it runs clean though all bleed points.
Close rad, thermo and heater bleed points and make sure rad tank is full.
Run engine for a few minutes water level may drop.
Stop engine and open bleed valves, some air may come out.
Top up water if needed.
Run engine until hot and the fans come on. Keep it going for 10 mins to get a flow through the radiator.
Repeat the drain and filling process using proper coolant.
If you live in a hard water area use premixed coolant or distilled water.
If you drain the flushing water hot (obviously) take care but don't refill until engine is cold.