Ok, let me try. If you are talking about the folded piping without filling, then I'm your girl. When applying a flange, you line up your raw edges and just do a long basting machine stitch to hold it in place. There is no turning corners. Then put your border piece on as if nothing different. Stitch your border pieces, top and bottom or side to side as usual. Press your borders out, but do not include the flange, that stays where it is.
Let me review a bit on how to measure for flange or borders. Always measure the center of quilt and cut your pieces to that measurement. Usually the outside edges of a quilt top will have many seams which will inadvertantly stretch the measurement. Find the center of a border and the center of the side and pin. Pin the edge of border to edge of quilt top. Now pin along making your top fit the border or flange. This will keep your quilt square and prevent rippling borders.
As a side note, I quit adding flanges to my quilts because they get in the way of machine quilting. There is no way to jump them with a long arm, and stopping and starting on my home machine is just too much trouble for me.