2K is as it says....a mixture of 2 parts....a paint, and a hardner/activator
If you check with any bodyshop/paint supplier they'll be able to supply details on mixing ratio's etc....
as a guide...VRS (not sure if there's one near you) supply most paint for around £40/litre.... you then normally mix in one of the following ratio's 3:1, 2:1 or some are 1:1...some require a thinner to be used, and that then becomes something like this... 3:1:1, 3:1:1/2....you get the idea....but like i say, the supplier will be able to answer any questions you have about mixing.
Acrylic is used mostly for older cars, such as a MK1 cortina (only car i've ever used acrylic on), and Cellulose is quite an old paint system, and doesn't stand up very well....the old red cars with pink/white bonnets were normally sprayed using cellulose. Enamel sounds like something tiles are coated in...
Where do you intend to spray the car?
If you're doing the whole car i'd really recommend a spray booth, it'll save you alot of time when it comes to the final finish!
Oh, and ignore Haynes....it'll mess with your head!