On a WIN10 Pc. i have a in-screen PC (no extra box), and a second screen connected by a cord/wire (forgot what its called)

is there a way to find

a) Which screen is the main computer / CPU etc..  and the other is just a screen..

and

b) the name/type of the second screen (not the PC) - so i can tell the retail store what ive got.

ba) the type of connection i have (I forget the word)

Ps Ive switched screens in the past so screen 1 is screen 2 and screen 2 is screen 1. so i cant rely on the screen numbers.