Morning - hope you're enjoying your new Alfa?
There is no such thing as a Haynes or Haynes type manual for the Alfa 159 / Brera / Spider.
There is the Alfa Romeo own dealer level software - called eLearn.
Imagine this as being like a digital Haynes manual, although a little more basic / less descriptive. it has a basic description and basic pictures for a massive amount of procedures of things you may need to do to your vehicle.
In theory this is dealer only tech and supposed to inform a trained dealer level mechanic on the basics of procedures required to make repairs etc on new models, so there is some implied knowledge of basic mechanics at points but it is literally step by step so you can't go too wrong. The hardest part is that it occasionally makes reference to specific tooling, however you usually just need to be a bit creative with what you have available and you'll be okay.
Luckily for us owners, the software was leaked some time ago and readily available on eBay, so you need to look out for Alfa 159 eLearn and you'll be laughing.