See here for Abbreviations.
The simplest edging you can make:
Work a chain, say, 5ds, p, 5ds (otherwise written 5 + 5).
As shown here, you can try out many variations.
In the same way that you join into a picot, work joining picots into the holes of a hem-stitched hanky. For the corners work a join nearer the corner and work a longer chain of 5 - 5 - 5 to go round it.
You could also make a small fabric bag for your tatting and decorate it with this chain edging. Make holes at half-inch intervals by using a stiletto like a Victorian lady, or a darning needle. The chain can then be joined into these holes. See the picture with the Beginner Butterfly pattern.
Ring: 3 - 3 - 3 - 3. RW (leave ¼″ thread)
*Ring: 3 + 3 - 3 - 3 RW (leave ¼″ thread)
Repeat from *
Ring 1: 3 - 3 - 3 - 3 RW (leave ¼″ thread)
Ring 2: 3 - 3 - 3 - 3 RW (leave ¼″ thread)
*Ring 3: 3 + 3 - 3 - 3 (join to Ring 1) RW
Ring 4: 3 + 3 - 3 - 3 (join to Ring 2) RW
Repeat from * and continue to work in zigzag fashion, leaving about ⅛" of thread between each ring.
Small ring: 3 - 6 - 3, leave ¼″ thread
*Big ring: 3 + 3 -2 - 2 - 2 - 2 - 3 - 3 (5 picots at the top), leave ¼″ thread
Small ring: 3 + 6 - 3
Repeat from *
To fit round a corner, say on a hanky, do small ring, big ring, small ring close together.
Ring 1: 3 - 3 - 3 - 3 RW
Ch 1: 3 - 3 RW
*Ring 2: 3 + 3 - 3 - 3 RW
Ch 2: 3 - 3 RW
Repeat from *
Starting Ring: 4 - 2 - 2 - 2 - 4 RW
Chain: 2 - 2 - 2 - 4 + (to last picot of previous ring) RW
*Chain: 2 - 2 - 2 - 4 + (to last picot of previous chain) RW
Repeat from * until long enough