I just love making fancy fold cards. They are so easy and so effective ! This one is called a Back to Front Apeture Card.
The measurements you will need are as follows :-
A4 card base in your choice of cardstock
Designer Series Paper - 5 1/2" 3 3/4"
Inner Card - Whisper White - 7 1/2" X 5 1/2" - Scored in half at 3 3/4"
You can watch my step by step video here :- YOU TUBE CHANNEL