- off, - off, +off, + off, remove old batts. Clean trays and hardware, and cable ends, use baking soda if lots of corrosion. Install new batts, put some of those felt anti corrosion discs on the posts if using wet acid batts, + on, +on, - on, -on, re-program the stereo presets and clock, done.
When you put the first ground back on expect a tiny arc and a little snap, as the computers, hood light, dome light if the door is open, and possibly some accesories (like a CB) do draw a key off power.
Happy trails!