Hi - I'm equally completely new to 3D printing, the Ender 3 V3 KE is my first printer, but have figured this out successfully this morning! I used Cura and the "Filament Change" post processing script (rather than the "Pause at Layer" script which I could not get to work

First, you'll need to install the V3 KE Profile so that the printer comes up on the list for Cura. Directions here (I'm using Windows 11 and just installed the .4mm Nozzle variant)
https://www.reddit.com/r/Cura/commen..._cura_profile/

Add Creality Ender 3 V3 KE definition and nozzles by vadim-danilchik · Pull Request #17519 · Ultimaker/Cura (github.com) Printer Definition (creality_ender3v3ke.def.json)
C:\Program Files\UltiMaker Cura 5.6.0\share\cura\resources\definitions

Nozzle variants go in:

C:\Program Files\UltiMaker Cura 5.6.0\share\cura\resources\variants\creality

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Then, with UltiMaker Cura v 5.6.0 installed and the KE printer selected, under EXTENSIONS > POST PROCESSING > MODIFY G-CODE select ADD SCRIPT and select the "Filament Change" option.

I found I had to slice and re-slice my file with each Script I put in (and to figure out which Layer I wanted the "Change Filament" script to run at). But after the final slice I Saved to Disk, put the gcode file on my USB key and the Ender successfully paused (and automatically retracted) at each of the prescribed Layers. I extruded an extra 40mm of filament once changing the colour (to remove any excess of the old colour)

Here is the result!

IMG_0241.jpg