Is the folded edge when folding fabrics over (parallel or crossway to the selvedge). Most pattern pieces need to have one side placed on the folded edge, this side is marked on the pattern as Foldline.
Fold the fabric (parallel to the selvedge).
Place the pattern side (marked as foldline) on the folded edge.
Mark the outlines (using chalk) and cut it out
Unfold the piece.