Welcome to Mobiflight.
For PMDG its verry easy.... Cause PMDG work with a "simulation" of Mouse Actions.
That mean every EventID is simular to a FUNCTION in the Cockpit..... And every Parameter means a MOUSE ACTION you like to emulate.
Here is the List.... http://myhomecockpit.de/PMDG_737NGX_EVENT_IDs_SP1d.pdf
Please check the LAST Page.... There all Mouse Actions are listed.
NOTE.... Right Single on the List is "2147483648" but here Mobiflight have a other range and there must be a MINUS in front ... so -
2147483648 ! All other Actions work as written.
So.... If you are not sure how to make this, simply get in virtual cockpit and check how you do it with the Mouse..... If a Leftclick move the Button then use the Left Click Parameter (536870912) on the EventID of that Function..... And a Mobiflight Button Press would simmulate a virtual Mouse Left Click on that Element.
Left Click is used for Momentary switches in 99% of Situations.
Encoders work mostly with Mousewheel UP and DOWN Parameters ( Also with Clicks but that i not recommend)
Multi Position Switches ( Like Rotary switches and ON-ON-ON Latching switches) have a Value Parameter ..... Starting with 0 Zero on Upper or LEfT Position and count upwards 1,2,3,4,5, and so on for every detent. Here you use NOT a Mouse Action !!!!! Use for the First Position Parameter 0 and so on.
This work in maby 98% of Inputs..... Only some Special need adavanced Logics.... But if you understand the System you will see it directly when you reach a "special one".