Upate info on aftermarket double din and necessary connections

[Morganator]

Hi all does anyone have an up to date guide on installing an aftermarket double din headunit and what adapters are needed?

Were possible i want to retain the factory dab and gps antenna, steering wheel controls and reversing tone. im only going for a cheap chinese stereo, but something newer and up to date features over the stock unit from 2012.

vehicle is a leon 2012 1p ecomotive 1.6tdi

Any advise or experience on this would be appreshiated

Thanks