Unfortunatelly thereīs no tutorial for the GameGadget, but is simple. All you need is the vmlinuz.bin from the sandbox or OpenSourceOS and any opendingux rootfs. No extra drivers or something else.
The majority of the emus work in the Game Gadget, but you should search for the OpenDingux version. Dingux versions, just some work... The same rule apply for the games.
To make links, put icons and such things you use the same ways of the Dingoo OpenDingux and you will find tutorials for that.
The only things that DON`T work are the brightness adjust, overclock and shotcuts that use the power slider button, since the Gadget donīt have a slider.