Download pattern here
Using the pattern in the link above, cut four of piece A (front and back of bag), two of piece B (bottom of bag) and one of piece C (pocket)
Also, cut one bottom and one pocket piece out of interfacing
Sew back of bag (A) and bottom piece (B) together (with right-sides together)
Fuse interfacing to the bottom piece to make more sturdy – not shown in picture below
Fuse interfacing to the wrong side of pocket (C). Finish off the edges of C with bias binding.
Pin pocket (C) to front piece (A) and then sew these to the bottom of the bag (with right sides together)
Turn right side out.
Use remaining pieces in matching (or coordinating) fabric to make the lining of the bag. Do not turn right side out.
Insert inside-out lining into the bag (wrong sides together)
Match up the edges of the bag and the lining.
Pin and sew the top of the straps together, making sure that once finished the seams face towards each other. Press the seams open (they will not be visible once the bag is complete)
Finish off the bag with bias binding.