OK, this is what I would do with the bias tape:
Take one end of the unfolded bias tape and pin at the top of the pouch by one of the end seams. (Fold tape over a bit at the beginning) Pin all around and then sew on. (Overlap the tape when you get back to the beginning by about 1/2".) Then refold the bias tape and either hand stitch to the inside or machine stitch. And presto -- pouch done! Clear as mud?