How do i install an image on Zgemma H2H

Newbie alert.
Zgemma H2H in post and will be untouched factory software. How do I install this image. Been reading articles on this forum for 2 days now and still unsure how to do this.
Not a complete fool but would rather ask questions beforehand to get it right, than brick my new box and work backwards.

Much appreciated.

thanks MasterG,

Ive read that article along with a 'few' others. But my head is spinning with 'bootloaders' and images such as 'openATV' VIX, etc etc.

Do I simply drop this download .php file into the 'root' of a USB stick. Put it in the back of the H2H and power-up?
Is it that simple?
No need to change the bootloader beforehand. Nothing?

thanks again

Got it, makes more sense now its downloaded as a .rar
thanks again, will drop you a line when new box is delivered and images is (hopefully) loaded and working.

Happy new year

thanks cazuela. Understood.
Unlike many things. Which is of course due to the fact that there's a lot of subjects that cannot be approached for obvious reasons. Makes understanding basic things very difficult until of course, you understand! Isn't that an oxymoron? anyhow, thanks to all who make the forum exist, v-grateful