See those fluffy pillows of batteries? They were making my laptop fat and ungainly, not laying flat on surfaces and making the keyboard hump up so typing was "uphill".
Fast, easy, everything fit just right. The directions were clear and straight forward.
You can do it, Give it a try. Get the full kit with helpful tools. Be sure to ALWAYS use a muffin tin for holding the various sizes of screws as you remove them and then re-use them.