Fitting After Market Head Unit To Yaris

[Yarisboy]

I know this question has been asked many times before, but the answers are usually short and not altogether that helpful

can anyone give me a fairly detailed description of installing a headunit in place of the standard tape player/radio? :o

I know the dash has to come off and that the headunit will go in place of the little black cubby hole beneath the current stuff.

thanks in advance