02 1.9tdi ghiaford galaxy hard to engage first gear

fist gears work , but if you cannot get it into first gear with out grating ( normally reverse will be at fault also) then it is not first gear but a clutch activation problem
if the gear is very noisy , it will be a clutch input shaft bearing or a problem in the bush/ bearing in the end of the crankshaft
if the bearing is faulty then 4th gear will keep jumping out of engagement
so check for air in a hydraulic system or a cable in a cable clutch

Hmmm Learn something new every day. Didn't know Ford had resurrected the Galaxy line, let alone put it on a van. Oh well. If Ford were kind, you should be able to access the back of the tail light assembly from the inside. There should be access panels, one behind each tail light assembly. Your owners manual should have the information. If not, a Chiltons/Haynes repair manual that covers the make/model/year will certainly lead you through the procedure.

check and adjust the step down rod connected to the transmission and carburettor. Remember that it is a 3 speed so the gear ratios will be wide and that hampers performance

have the timming checked

If this is a red flashing light beneath the temperature guage it means that you do not have enough coolant. Top up the large white ball shaped reservior at the right hand side of the engine compartment just behind the battery.

Probably a bad vacuum line. Check of broken or cracked vacuum line under the dashboard....

thats common for the reverse gear to grind if you go right for it i always go to fist then reverse. it sounds like you might have a week slave cylinder and the pressure is to low to go into a high gear does this happen in 5 th also or only 3 rd?

this is a shift actuator fault

replace the heater core. its leaking

About the only thing you yourself can do is to check your transmission fluid level, and replace if necessary.
Sadly you will probably need to take the car into a service center to be tested properly.