How to get RPM signal from old school coil and distributor setup in Ecumaster ADU

Hi folks, I have a question about how to wire in a rpm signal to the adu from ecumaster on an old engine that has a single coil and distributor. Is it simply just connecting a digital input (digital input 1 in the case of ecumaster adu5) to the negative post on the coil and choose RPM on a new digital input? If so, how do you select the "trigger edge", number of teeths, etc?

If anyone could provide a good starting point here it would be greatly appreciated :)

I dont think the inputs would be designed to cope with the ~400V spike from an ignition primary. My suggestion would be something like this which will convert the coil spike down to a 5V square wave: https://www.autosportlabs.com/product/coilx-rpm-input-adapter/

Thank you very much for the help. I will try that solution.