You do not have to take anything apart to install the new one, that's why that notch is in the cover. Hold the new one vertical and slide it over the charging handle, then turn it longways and slide the top into the receiver then start at either end and push the bottom in, working your way to the other end.
You can take it out the same way, pull the handle back to the notch, to get a gap between the cover and bolt, then push in on the either end of the cover and pull the edge out, then just work it out of the receiver, turn sideways and off the handle. Being bendable allows you to get it in and out.