I saw a few of these on Etsy recently as I was buying laminated cotton for my seat covers and have been dying to have a go ever since!
I cut a rectangle of laminated cotton (I love this Robert Kaufman cheeky monkeys design!) and a rectangle of chalk-cloth fabric both about 32cm X 46cm. I also cut another small rectangle about 13cm X 9cm of the patterned laminated cotton.
I then hemmed 2 sides of the smaller rectangle as shown here with a generous hem at the longer edge:-
I placed this smaller rectangle on the chalk-cloth and tacked it to the Left bottom corner. I then sewed a vertical line 3cm from the RH hem as shown. (note the top edge in the picture is not sewn to the chalk-cloth but left an open pocket)
I sewed along 3 edges then trimmed the fabric close to the stitches. I used a long stitch at around 3 in length as I didn't want to perforate the fabric too much and risk tearing.
I then turned it inside out.
Before top stitching and sewing up the remaining side I again got out the sellotape!
So here is the finished result - a chalkboard on one side complete with holder for chalk and pocket for wipe cloth.