1) the LPR(low pressure reg) comes from under the barrel and HPR(high pressure reg) is in front of the grip frame.
2) from my pic, some have gone a step further and installed a hammer bumper(which is the oring on the left of the pics i shown), after breaking the red loctite holding the hammer to the ram shaft. you don't have to do this, unless you want to get into polishing and a lot of DIY mods.
3) LPR: follow this tutorial
on how to take apart and service the LPR.
4) HPR: taking apart the top part is difficult. not a crazy skilled job, but hard to do without marring or making idiot marks on the reg. follow this tutorial
5) finally, follow this tutorial
for the ram.
6) after putting the regs and ram back together, its now onto the "idiot" type checks, because we've all made them, so its no slight upon you.
6.1 make sure that the hole on the bolt is down.
6.2 make sure that the bolt pin is riding in the ram properly(you want it in the slot)
6.3 make sure that you have a good fresh battery
6.4 make sure that you have air in the HPA tank
7) after all of that, wake you way over to ICDO. we hang out there(only visit here) and are more apt and more readily answer questions there. not to say that PBN is bad or anything, there is a wealth of info here, but its just easier over there.
8) contact me for the frame mod and a new harness.