Summarize the following:
For this clutch, you will need three different fabrics: two for for the outside of your clutch and a fabric for the lining. All fabrics should be quilting weight cotton fabric. To be safe, you may want to get a yard of each fabric. You will also need fusible interfacing, and then any tools you like to use to sew, like a rotary cutter, pins, a ruler, etc.  For a really cute clutch, use two different designed fabrics that work well together for the outside of your clutch. You could use fabrics of the same color, or different colored fabrics. Both fabrics will show, so make sure you like the way they look together. Because you will have lining, you can choose to use any type of fabric. Just make sure the fabric you choose is durable and will hold the items in your clutch. Quilting weight cotton is good because it is heavier and will hold its shape better, but there is flexibility here. For your main fabric, measure and cut a piece that is 12.75 inches by 19 inches. For your second fabric (this will be the flap in the envelope) cut two pieces each measuring 12.5 inches by 5.5 inches. Then, the lining needs to be 12.5 inches by 28.5 inches. And finally, measure and cut the interfacing to 12.75 inches by 29 inches. Place your main flap fabric on the table with the decorated side face up. Then, place your flap fabric on top of your main fabric with the decorated side facing down (the right sides of the fabrics should be touching each other). Then, line them up so the long side of the flap fabric (12.5 inches) and the short side of the main fabric (12.5 inches) are together. Sew a quarter inch seam along the top of the lined pieces, or the 12.5 inch side. Make sure you don't sew along the 5.5 inch sides of the flap fabric. You want to leave those open and only sew along one side of the fabric. Place your other piece of flap fabric at the other end of the main fabric, with the right sides of the fabric facing each other and the two 12.75 inch sides lined up. Sew another quarter inch seam along the top of the fabric, leaving the two 5.5 inch sides and the middle 12.5 inch side open. At this point you should have your long piece of main fabric with the two flap pieces on each end of your fabric. You should be able to see the right side of your main fabric, but only the wrong sides of your flap fabric. Flip your flap pieces over so that the fabric is one long line. Then, iron the seams so that they lay flat. Turn your fabric over so that the wrong side faces up and the right side is down. Place your interfacing shiny side down on the wrong side of the fabric you just created. Line it up and press it down so it adheres to the fabric. Once you have pressed the interfacing on your fabric, fold it in half, so that the two flap pieces meet and the interfacing is on the outside of your fabric. The decorated side of your fabric should not be showing. Sew along the right and left sides of your fabric with a quarter inch seam, starting from the flap and moving towards the end of your main fabric. Take your lining fabric, the piece that is 12.5 by 28.5 inches, and fold it in half with right side facing in, so that you have a piece 12.5 inches by 14.25 inches. Then, sew along the 14.25 inch sides with a quarter inch seam. Take your clutch at the open end and turn over the top edge, where the flap fabric is, about a quarter of an inch. Press your fold down and iron it out so that it stays in place. Do the same with the top edge of the lining, keeping it with the wrong side out and right side facing in. Take your clutch and turn it so the fabric is on the right side. Iron out your fabric to remove any wrinkles, and press down the seams. Then, place your lining inside your clutch, by pushing down the corners of your lining into the corners of your clutch. Make sure you leave the lining inside out. Position the lining so the top of it sits about an eighth of an inch below the top of your clutch. At this point, the right side of the lining will show when you look in your clutch. This is why it could be fun to use a cute color or pattern for your lining so that when you open up your purse you don't just see a white or black lining. To attach your lining to your clutch, you'll need to sew a top stitch. Start at the right or left seam of your clutch and sew a straight line along the top of your clutch, about an eighth of an inch from the edge of your fabric. Then, sew another line, starting again at a seam, about a quarter of an inch from the fabric edge. This will attach your lining to your fabric. Take your clutch and fold it over so that you can see about three quarters of an inch of the main fabric at the top of your clutch. Then, fill it with your items and you're done! If you want extra security for your clutch, you can add a button or two to the top of your clutch so that you can button it closed while you are holding it. However, the fold in the envelope should be long enough that nothing should fall out of your purse easily.

Summary:
Gather your supplies. Measure and cut your fabrics. Line up your main and flap fabric. Join the second flap fabric to the main fabric. Open up your piece and attach interfacing. Fold your fabric in half. Fold and sew your lining fabric. Iron out the top edge of your clutch. Flip your clutch right side out. Sew along the top edge of the clutch. Fold your clutch over and finish.