Original Prusa i3 to MMU2S upgrade

Are there instructions/guidance/flow for folks who will be assembling the MK3S+ and the MMU2S at the same time?
From what I see so far, the guidance is for an upgrade flow.
I would prefer to do it all at once.
Thanks!

STOP WHAT YOU ARE DOING RIGHT NOW AND START AT CHAPTER 4 UNLESS YOU HAVE THE TIME TO COMPLETE THIS PROCESS IN ONE DAY. Proceeding any further will disable your printer until this process is completed. It is possible to build the entire MMU assembly without modifying the existing extruder which will render your printer inoperable until the MMU is fully installed. Completing the install will take between 4-12 hours depending on your level of dexterity and experience in mechanical assembly. To avoid an extended printer outage if you do not have the time to complete this project in one pass simply skip to Chapter 4 and follow the instructions through Chapter 6 step 19, then proceed to the extruder modification section for your specific printer model before proceeding on to Chapter 6 step 20. If I had known this before I started my printer would not have been offline for almost a week.Also, do not even bother with the buffer assembly as it is completely useless and will do nothing but add drag which will cause your filament to under-extrude. Same with the 5 long PTFE tubes that attach to the back of the MMU, just cut them off at about 10cm as they will just add drag and cause the same problem. I ran the First Layer Calibration 20 times before I figured out what was happening.  As soon as I removed that stupid buffer assembly and cut the long PTFE tubes everything started working great.This upgrade is worth every penny.

Navigating these instructions SUCKS... I want to BUILD it before I tear apart my printer so that my printer does not become unusable for 3 days while I figure out all of these instructions. RE-ARRANGE THE INSTRUCTIONS, so that you buidl the unit FIRST, then attach it to the printer

Great instructions overall. It took me about 3 hours to assemble plus about an hour of tinkering in PrusaSlicer (120 removal, 2 cooling moves for PLA) and tuning (F.I.N.D.A. and runout sensor tuning). PLA works perfectly well now using a range of filaments. Definitely read comments before performing the step. I also had to replace the PTFE tube from the selector to the hotend with one that's got a bit more slop (2mm instead of the 1.8mm included) to help reduce the unload/load issues getting stuck in the tube. PETG also seems to work fine with basically stock settings. It strings more than I would like for longer prints, but it's fine for small stuff now. TPU is having false negatives on load. The chimney on the extruder body is just not reliable enough for the variable width of TPU. I'm printing the following upgrades: QoL item since my PTFE falls out or has large resistance once tightened: https://www.prusaprinters.org/prints/6605-prusa-mmu2-ptfe-holder-m10-passthrough-adapter More sensitive chimney: https://www.thingiverse.com/thing:3554066 I'm not a huge fan of the design, so something more compact might be nice. More reliable/easier maintainance selector: https://www.thingiverse.com/thing:3725680

I ate all the Haribo before I found the instructions only to eat them during construction. Clearly the bag needs labelling to advise this!