Hose:
You arrive at the job. Lift your hosereel out of the van, put it on the ground. Now, you need to connect it to your pump - so there has to be a short length of hose attached to the outlet side of the pump (this can be straight on to the barbed connector which screws onto the pump outlet, and held in place with a jubilee clip) the other end has to connect to the reel centre so if you're using a standard hozelock type, you need a hozelock connector. Be aware these things
always leak
...if not straight away then in a very short time. Pick up your pole (I use an 18' Predator - reaches most first floor and is light enough to use on ground floor) and the end of your hose. Try to lead your hose round convenient posts, trees or anything to guide it and stop it dragging across flower beds etc. As you work away from the van you pull the hose after you, when you've finished disconnect your pole hose and leave the reel hose lying on the ground. If you've been careful about how you lay it out, it should reel in again fairly easily.
Battery:
If you use the vehicle battery to power your WFP be sure it's in good condition and well charged - you don't want to get to the end of the day and then not be able to start your van :
Cheers,
Ian