Ok; it covered before somewhere but here goes:
1. Park car on slope with nose upwards (aids air bleeding),
2. Put heater on highest setting.
3. Remove thermostat and thermostat housing top.
4. Fill to top of thermostat housing via thermostat housing.
5. Replace thermostat (make sure its a dual acting one with jiggle pin).
6. Replace thermostat housing.
7. Fill rest of system using a funnel to full from the small bleeder hose that is on top of the thermostat housing and runs to the coolant overflow bottle; hold hose in air above highest point of engine or radiator while doing this).
8. Replace bleeder hose and top up over flow bottle.
9. Screw cap on overflow tank loosely one turn.
10. Start engine (heater still on max setting) run for 10 minutes at 2000 rpm or go for a 10 km drive.
11. Let cool top up and tighten cap.
12. Have a beer and toast the Ford engineers who designed such an air lock prone system.
If you're changing coolant brands flush with distilled water before doinf this (i.e. fill with distilled water and go for a 20 km drive, let cool then change coolant).