After jerry-rigging an old i3 to work with a spare e3 mainboard, I have a lot of very useful information on setting u a marlin printer from scratch. Firstly, you want to make sure all the hardware is configured correctly and wired properly. This is mainboard-dependent, so make sure you reference relevant documentation for your mainboard of choice.

Some relevant reading material:

• Marlin Configuration Docs
• Marlin Troubleshooting Guide

1. Install vscode (ew) and make sure you have the following extensions installed:
   • Patformio
   • Auto Build Marlin
2. Clone the repo then open in vscode
3. Open Auto Build Marlin
4. Navigate to Marlin Firmware Configurations and pick a configuration that is similar/matches your hardware
5. Copy the relevant *.h files to Marlin/ in the repository.
6. Build using auto build marlin.
7. Verify It Builds