Hey there, Eevee is part of an experimental version of Blender and is not officially released yet (it’s not even in beta yet), so I would hold off on downloading it for now unless you’re just super curious and want to try it right away. You can find it here under the 2.8 label: https://builder.blender.org/download
As for #2 and #3, we cover those kinds of things quite extensively in our modeling learning flow: https://cgcookie.com/flow/modeling-in-blender
Lastly, Blender can be downloaded as an installed program or as a portable .exe, and your computer will always open the files with the installed program. When you download it, grab the installer instead of the .zip: https://www.blender.org/download/
Hope that helps!
