You need python 2.7 or 3.7 installed on your computer.
Octoprint needs the Palette 2 plugin installed https://gitlab.com/mosaic-mfg/palette-2-plugin
Grab the P2PP scripts, unpack it somewhere on your computer. There are instructions for setting up & configuring the p2pp scripts. Decent video at https://www.youtube.com/watch?v=JuTdq-IlRj4&t=1s

Scripts are at https://github.com/tomvandeneede/p2pp

Other useful links: https://support.mosaicmfg.com/Guide/Slic3r-PrusaSlicer+and+Chroma+Setup/76

Configure PrusaSlicer for p2pp

Printer settings tab – Capabilites:
extruders = 4
single extruder multimaterial = yes
enable variable layer height = no

once those are done, you will have options for “Single extruder MM setup” – select that and set all those values to zero / unchecked.

For extruders 1 – 4, change the filament color so you can see what is happening on the Plater tab.

Save the new printer profile as a new name.

Print settings tab –> Multiple extruders –> Wipe tower -> Enable= on, Prime all printing extruders = off

Output options-> Post processing scripts -> insert path to p2pp.bat
Output filename format -> edit format string so that it ends in .mcf.gcode instead of just .gcode

Now go back to printer settings tab
Custom Gcode –> Start G-code. Insert code in bottom of that section: code from https://github.com/tomvandeneede/p2pp
edit the code inserted: P2PP PRINTERPROFILE= THe value for this needs to come from a previously generated chroma processed gcode file. The line will begin with 022. Copy the string (without the initial capital D) and paste that as the value for “P2PP PRINTERPROFILE”

The next couple values can come from the Chroma postprocessor app. Start it, edit the printer profile, and look at the values for Min|Max|Early Transistion Length and Target Position (defaults are probably 140mm, 140mm, 140mm and 40%).

Edit the values for
P2PP SPLICEOFFSET= Make this number 40% of the Min Early Transistion Length (ie; 140mm – 40% = 56mm) Use the actual number found in your Transistion Target field – might not be 40.
P2PP MINSTARTSPLICE=100 this is due to hardware limitations, leave it alone
P2PP MINSPLICE=80 Same as above

The values for P2PP MATERIAL_TYPES 0_0_0 are as follows Heat factor, compression factor, cooling factor. Used for tuning. You can look at material profiles in the Chroma post processor to see what you have set in there

;P2PP LINEARPING (leave this in)
;P2PP LINEARPINGLENGTH=500 – might need to tweak this – too low and printer may pause. too long it it may not be well calibrated. Dont go below 350
;P2PP EXTRAENDFILAMENT=150 – figure the length of your hot end + bowden tube and add a little extra so you can pull filament out

Not sure about the SIDEWIPE settings yet…

Now in the “After layer change G-code section append this code: ;LAYER[layer_num]

Now off to Filament Settings Tab
Go to Advanced–> Rammer settings button. Set Total Ramming Time to zero, No Ramming at all.

Now to configure Purging Volumes.
Go to Plater tab, click Purging volumes button. To get the number for the unloaded and loaded fields, take the number from the Chroma post processor, look in the printer profile -> Transistions tab and see what number the Min Transistion length is. That number is in millimeters. Prusaslicer wants cubic millimeters. 1mm of filament is basically 2.4 cubic mm, so multiply the min transistion length number by 2.4. Then divide that number in half, and insert half in unloaded and loaded fields. If you need to finetune it later, like when switching from a dark color to light color, you could adjust the ratio between loaded / unloaded, but the total of the two boxes should still equal (min transition length * 2.4).