There is no need to either bend or cut off the tab at the end of the brake pad holder. To get the old pad out, use a vise, vise grips or woodworking clamp to grab the pad and then a large screwdriver to pry the holder up away from the pad. Sometimes a second smaller screwdriver is needed to help with the prying. To put the new pad in, I usually lube the sides of the pad with dish soap,then use vise, vise grips, woodworking clamp, etc to squeeze the pad slowly into the holder while cajoling the sides of the pad past the edges of the holder with various prying tools. This is usually a bit tricky and patience-trying, but eventually works perfectly.

Note that if you don't lubricate the pads then there is no way they are going to go in.