Liner Not Fitting Right
We put the liner in and after about 4" of water the liner started to slip off one side of the pool. There is barely an inch of over lap left. Should I try to stretch the liner and continue to fill or try to pump the water out and attempt to adjust the liner. Thanks
With only an inch of overhang left you may not have any choice but to drain and start over. You could wait until the hottest part of the day and start filling again, see what happens. Or you could drain and try pushing the bottom out to the sides and maybe gain some more liner. Work only in full sunshine and quit for the day when the liner starts to stiffen up, as it does soon after the sun is off it.
Hopefully you have not cut any holes for the skimmer or return, this just complicates things. Leave that for when you know the liner fits. If you can fill it to just below the openings you should be in good shape.
Another thing I do that might help is tuck the excess liner back into the pool. This give you an even two inches or so on the outside so it looks better. It also make a double layer of liner for the coping to go over. This makes a tighter fit and harder for the liner to slip.
Most importantly, make use of the sun.