hi first of all you need to fix the gripper approx 1/4" away from the skirting with the spikes faceing in to the wall butt each stick of gripper side by side with no gaps
underlay goes rubber side down or if you have the foam underlay fit it so that the writting on the underlay is on top( so you can read it otherwise its upside down
roll the carpet out and if possible flush one side ( the salvage edge not the cut side) against the wall leaving it up the skirting no more than 3mm
once you have done that you can now rough cut the carpet in to approx 3" up the skirting ( MAKE SURE YOU HAVE ENOUGH CARPET TO REACH INTO DOOR FRAMES AND ALCOVES IF YOU CAN BEFORE CUTTING)
once you have done that use a bolster chisel 4" head if you have one and push the carpet into the gripper, then rub the bolster along the top of the carpet onto the gripper to make sure it grips, once you have done that go to the other end of the room with and start to stretch the carpet from the middle moving to the left side then over to the right placing the stretcher 1/2" from the wall
if you have settings on your stretcher or numbers set it to number 5, if carpet is thin go lower and if it has a long pile set it higher
before you start to stretch make sure you hold the head of the stretcher tight into the carpet or it will slip and rip if you do not have enough pressure on the head, DONT GO TO MAD WHEN KICKING AS YOU CAN TEAR THE CARPET !!!
once you have stretched the length you can start to cut the carpet, bend the bit you will be cutting off down to the floor and then cut the carpet slowly leaving about 4mm to tuck into the gripper, once you have fitted that wall you can then start on the side walls
starting at the first wall that you fitted gently stretch the carpet onto the gripper working your way down to the other end than fit that wall
last of all depending that it is a square room, stretch the carpet accross the room hocking it onto the gripper by pushing it down with you fingers, watch the spikes!! once you have done that you can fit the last wall
door bars should be fitted that they are under the door when closed, when fitting into these allow about 4mm to fit into the bar
hope this helps