Cut pieces in the following order.
From green print, cut:
2 10-1/2-x-13-1/2-inch rectangles
2 2-inch-diameter circles
From synthetic leather, cut:
1 2-1/2-x-24-inch strip (or desired length for strap)
2 1-1/2-x-20-1/2-inch strips
From light green print, cut:
2 10-1/2-x-15-1/2-inch lining rectangles
From fusible interfacing, cut:
2 10-1/2-x-15-1/2-inch rectangles
From clean, heavyweight vinyl, cut: 2 10-x-16-inch rectangles
Fold bag rectangle in half on seam line; sew together side edges (Diagram 2). Finger-press seams open.
Center brad ring on bag synthetic leather strip, 3/8 inch from bag top edge (Diagram 4). Trace inner hole of ring on synthetic leather strip. Cut away marked hole, cutting through synthetic leather and lining at same time (use a seam ripper to make a small cut through all layers to start hole). Following manufacturer's directions, secure a brad ring to side edge of bag. Repeat to secure ring to opposite side edge.
Fold one long edge of synthetic leather 2-1/2-x-24-inch strip under 1 inch (Diagram 5). Finger-press under 1/2 inch along remaining long edge. Topstitch 1/4 inch from folded edges to make bag strap.
Insert one end of strap through brad ring and fold back 1 inch to underside of strap. Sew through all layers to secure strap (Diagram 6). Repeat with remaining strap end and brad ring.
Turn under edge of green print 2-inch-diameter circle; baste. Blanket-stitch fabric circle to center top of light green print lining, 1/4 inch from edge, leaving a 1-inch opening at top. Insert one half of magnetic snap closure into fabric circle pocket; blanket-stitch circle closed. Repeat with remaining green print circle and other half of closure on opposite side of lining.