Steps required to make printable object ????

[lycan]

Gday All,

Ok as I have jumped into the deep end without any floatie`s, I need some simple ( and I mean SIMPLE ) descriptions of what is required to create a printable object.

For argument sake if using rhino 5, autodesk or blender to design my shape, once I am happy with the appearance and size do I have to select other components like rendering, running it through Rep3g, makerware etc etc.
Oh and one last thing, the files that are downloadable off thingiverse, are they already all good to go, as in download one, send it to your printer and it should work or are there are adjustments / conversions to be made first ??.

Yep really stupid question but unless you ask you never learn.

Cheers
Steve