How do I wire this shelly I3?

Hardware
1

I have this Shelly i3, but I am completely stumped as to how I should wire it to my Gira 3 way impulse-switch, can anyone please help me?

2

Have you read the documentation?

All 3 inputs are just “momentary” switches. If connected to “L” they are on (or off if you configure the inputs -3- as flip switch).

See here
https://shelly.cloud/knowledge-base/devices/shelly-i3/

In the pdf manual:
SettingsButton Type •Momentary – When using a button. •Toggle Switch – When using a switch. •Reverse inputs - If you enable this option, the but-tons On/Off position will be inverted.Longpush Duration •Min - the minimal time, that the button is pressed and hold, in order to triger Longpush command.Range (in ms): 100-3000 •Max - the maximum time, that the button is pressed and hold, in order to triger Longpush com-mand. Range for max (in ms): 200-6000MultipushThe maximum time, between pushes, when trigger-ing a multipush action. Range: 100-1000