TL,DR:

hellen-one is a toolset to produce custom PCBs by merging gerber files of known proven functional modules into trivial frame PCB with mostly just the main vehicle connector.

• fork https://github.com/rusefi/hellen-example/ repo to get github actions and meta files
• make sure github actions are enabled/enable github actions on your fork
• replace xxx and yyy in revision.txt with name of your board
• create youboard.kicad_pcb from proven modules using KiCAD 6 or 7
• push into github to trigger hellen-one gerber expert and gerber merge (that's where the hellen magic happens! for instance gerber export is taken care by export.sh script which github action would invoke automatically. Just watch for the yellow circle to turn into a green checkmark.)
• (sorry rotation only by factor of 90 degrees at this point)
• order your using fabrication files from 'boards' folder!

Please see how some of the open source boards are done and follow the pattern:

Open Source Boards

• https://github.com/rusefi/alphax-4chan
• https://github.com/rusefi/uaefi
• https://github.com/rusefi/alphax-2chan
• https://github.com/rusefi/hellen154hyundai
• https://github.com/rusefi/hellen121vag
• https://github.com/rusefi/hellen88bmw
• https://github.com/andreika-git/hellen81/

This repository contains all scripts and data to create Hellen One boards for rusEFI!

See also https://github.com/rusefi/rusefi/wiki/Hellen-One-Platform

Hellen One is a DIY PnP ECU board construction toolset.

Do you have a car with a rare or non-standard ECU connector pinout? Do you want a custom DIY ECU but don't want to design it from scratch?

Then Hellen One is for you!

Please see Hellen One Wiki for more info:

https://github.com/andreika-git/hellen-one/wiki