Gcode noob needs help

So I watched a video that Ryan put on the site by “Some Old Guy” (His words, Not mine lol).
In it he explains tool changes and one method caught my eye.

G0 Z0 -Moves Z to Material
M84 S999 -Keeps motors engaged
M18 Z -Releases Z motor
M00 -Pause for Operator

I like this method. Aside from the fact that it will stop above the end of the last cut.
Thus you would have to assume where the material top should be while resetting your Z axis
after your tool change.

The other method involving moving your tool to a safe location is nice but you would have to
alter your safe location for every different project because you will position your tool holder at different location for different jobs. I’d like to have one easy script to remember.

For safe could I use G0 X0 Y0 Z0 ?
Because wouldn’t that be my starting point/Stock Box point? That would most likely then be on
the topside of my stock and I wouldn’t have to worry about then locating the material topside on a spot that’s already been milled.

Now, on to my next question.

I’ve never played with gcode before in its raw format. I’ve always just let Fusion 360 spit
out whatever it does after I post. How do you add it? I already assume that when fusion posts the code I can then transfer it to notepad and add this script somewhere. but is that it? Did I answer my own question?