There's a series of guides on converting the Ender 3 over. In the end it's quite similar to the ender 5. It may help clarify some things.
https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+Maestro+Guide+Part+1:+Wiring/37
Part 5, for calibration may be what you're after right now.
https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+3+Mini+5++Guide+Part+1:+Wiring/87
The second link is for a more recent guide using RRF3, which is still in progress.