I still prefer the thicker insulation sheets. They come 4' x 8' but are easily trimmed down to fit a space. Hinge 2 pieces with duct tape. Have 2 people and batting or flannel larger than the size you have. Check for size so you can trim to about 2" bigger than sheets. Remove batting from one corner. Then spray that sheet area with 3M 77 spray, available at office stores. Gently place batting in position starting at one corner, and smooth it out as you go. Continue the process til all of the sheets are covered.
I have mine hinged closed at present as I usually don't need a lot of design wall. I sprayed the back of 1 sheet like I did the fronts. when I have a larger project I simply open up the design wall.
After we completed my wall a friend came over and we gridded the wall using colorful ribbon in a 12" x 12" grid and diagonal lines corner to corner.
There are lots of methods to use. Choose one you like.