honda fit 2010 stereo

I have a Honda Fit 2010 and I recently bought a new Stereo. Now I need to set the new stereo up in the car. My problem is that I can not recognize which wires I must plug in the stereo to command it from the controls on the car's wheel (volume, next track and mode) and the panel's light in the stereo. And which are the wires to plug in the stereo included in the car. Is there any link to download these technical specifications?

metraonline.com has a lot of the information you need.  It is not as easy as you are thinking to do steering wheel controls.  Metra sells the hardware to pull that off as well.

Also use that hard wire for the new head unit, not just the SWI.

And I should have kept my hands off the keyboard, that car like the Yaris is made in factories around the world including Brazil, China, Thailand, the UK etc. etc. AND interiors differ

And an antenna plug adaptor, it uses a "FAKRA" type plug (like BMW, VW etc.) in the European type market. So the following required:- Lead adaptor. SWI interface. Aerial adaptor. Probably a fascia plate as well.