Grove V2.0 shield and Arduino Mega 2560 for DCS Up Front Controller panel

Just by quick intro, I'm attempting to build the UFC using Arduino Mega and Grove V2.0 shield, and I am a complete electronics novice. I've sorted the 'switch' components without issue but I am struggling to understand how to implement 5 separate 4 character 7 segment displays via the Grove Shield sat a top the Arduino. I can easily connect 1 display using suggested D2 plug but there does not appear to be an obvious method of defining a second or subsequent connecting for other displays that show different information. How do I define/assign subsequent 'addresses' for the other displays?. Despite youtube and google searches, this info is not at all obvious.
Many thanks for your time,

Links to all the hardware please. Schematics too.