Original-Prusa-i3 VS Prusa3

I've been effective with OpenSCAD and FreeCAD.

OpenSCAD is good for enclosures: https://github.com/sbambach/MarksEnclosureHelper

and mechanical systems: https://github.com/prusa3d/Original-Prusa-i3

Don't think of it as a programming language; that will hurt you. Think of it as a specification language. That helped me.

Being the printer already assembled and working, I am looking at pg. 12 of the printer manual downloadable from prusa3d.com, chapter 6.3.1 Calibration flow and wizard, showing two different scenario... one for kit and one for assembled printers. Am I correct assuming I can just go through the latter? Also it's not very clear to me if that's the process I have to go through each time I turn the machine on, before attempting any print.

TLDR: replace the adapter-printer if it's worn.

They’re usually bought at https://prusa3d.com

On top of that, people simply don't know what they're doing. For example, the Prusa MK3S+ STL files are licensed under GPLv2, which does not make sense because there is no source (the source files are GPLv3 for some reason). But if you look at the remixes, the majority are licensed under some Creative Commons license end even the Public Domain. All those remixes are mis-licensed because only the GPL is compatible with the GPL.

you are right, but many people have asked for this.... reddit, github.. even on prusa3d.com but they dont care...

The BOM (of sorts) of the MK3S exists here.

No corresponding source for the parts is available? I don't seen an MK4 branch in there, unless they ditched openscad entirely (even then at least STEP files should be provided if it's still Open Hardware).

Original-Prusa-i3/extruder-body.stl at MK3S · prusa3d/Original-Prusa-i3 · GitHub

From prusa3d.com:

Back when Prusa-the-person designed the original i3 I'm pretty sure there were no other Free Software CAD tools than openscad. I don't think it's a huge loss if they abandon openscad (as long as STEP files are provided) since the source for the i3 was uhhh... not exactly the paragon of openscad design (magic numbers, magic numbers everywhere). There's a variant which is parametric but hasn't seen any updates since before the MK2. My reprap is based on some bastardization of the Wilson reprap and my own custom 10mm variant of the old community i3 repo, but I managed to make it even worse because I was looking at the z-axis parts upside down and completely hosed the coordinate system and other fun things (the joys of hacking on a large blob of mediocre openscad while also not knowing anything yourself about cad...) and then I got busy and I'm so distant from it now I can never get myself to go back in and fix it.

Prusa also contributed actively to rep rap, making improvements on the mendel printer, and improved the printer through a couple iterations until he hit the third iteration(i3), that is the basis of the MK series. Before shipping his own product, he shared the design on GitHub, and plenty of low cost manufacturers picked up on his source and blatantly produced their own i3 printers.

https://github.com/josefprusa/Prusa3 is the repository of the Prusa i3 (without "MK" at that time, but I guess it's MK1 then...). I found https://github.com/josefprusa/Prusa3/blob/master/box_frame/common.tdoc which has some vitamins for the frame; you may look around if you find further *.tdoc files with more parts. Maybe also https://github.com/josefprusa/Prusa3-vanilla . Also, some README mentions a documentation file, but I could not find it quickly - might want to check for yourself if you find more docs there.