If you aren't sure how the parts will go together before you take it to pieces, use a digi camera to take photo's of the process in stages.
Anyway, the simple way....at the back of the marker you will find a pin that you can take out that holds the main spring and lots of other bits......DON'T TAKE THIS OUT YET!!!!
Undo the two Allen bolts that hold the trigger frame on to the main body, remove the Allen bolt that holds the feed pipe to the front block and slide it out and remove the valve rod and cup seal. This will allow you to handle the body easier.
Hold the back of the gun against you stomach, and pull the pin at the back out. Remove the back velocity adjuster, and remove the spring guide and main spring. Turn the gun body upside down holding the end with one hand and tap it until the bolt and hammer fall free.
If you really want to take the valve body out you will need a hammer and dowel punch, and will need to note the direction it came out, or you will never get it to work again until you do. I really suggest that you don't bother with the valve as the seals will as good as last for ever and not need replacing.
Assembly is the reversal of disassembly.
Good tips
Don't over oil
If you are using CO2 it will freeze the moving seals and ruin them
A smear of paintball oil on all seal edges is enough
A drop or two of oil in the ASA hole (Part that the CO2/AIR) screws into, will lubricate the gun for the day
Feel free to PM me if you need more help...
Enjoy...Nobby