first if you do not have an electric fan you will need to remove the fan clutch.
the fan clutch is reverse threaded so you will need to turn it clock wise to loosen and counter clock wise to reinstall it.
once that is off you need to take the two clips off the fan shourd.
once the clips are out pull up the shourd far enough to pull the fan out.
dissconnect the hose going to the exspansion tank and the hose under the shourd form the tank to the radiator, remove the shourd, you should have full access to the tstat.
using a pick are small screw driver pull out the clips on the radiator hoses and remove
hoses.
unbolt the tstat and remove, for istall reverse this.
to bleed the cooling system un screw the bleeder screw in the exspansion tank and fill till there are no more bubbles coming out of bleeder/ reinstall bleeder screw and start car ( with heat on in car) top off coolant and reinstall cap/ test drive to make sure car doesnt over heat and then check coolant once car has cooled off, top off if needed.
BMW Technician
5 years independent experience, 5 years BMW dealer experience, BMW factory trained, State liscensed