Trying to download the free Cubas with Yamaha AG06 mixer

can someone please help me?

i bought a yamaha AG06 mixer for my podcast im about to start. Problem is i cant start until i get this cubas software downloaded… also im not getting any sound from my mics to the mac speakers… this is getting very frustrating… im at the point where its asking me for my steinberg ID and password i type it in and its telling me it doesn’t exist??? but yet here i am talking to you people???