There are several ways of starting the ring. One way is to crochet into a Magic circle. Another one is to make a ring of chains joined into a circle.
Either make a Magic Circle or Chain 5, slip stitch into 1st chain to create a circle.
Row 1: Chain 3 (counts as first double crochet), in same space (2 Double crochets, chain 2, 3 double crochets), chain 2. In next 3 chain 2 spaces (3 double crochets, chain 2, 3 double crochets, chain2) . Slip stitch into the top of beginning chain 3. Now you should have a total of 12 double crochets and 4 chain 2 spaces.
There are several ways of working the beginning corner. I think the easiest way for a beginner is the following...
Row 2: Slip stitch over the next 2 double crochets and into the center of the first chain 2 space. Chain 3 (first double crochet), work 2 double crochets, chain 2, 3 more double crochets into the same space (first corner made), chain 2, (3 double crochets, chain 2, 3 double crochets)* into the next 2- chain spaces, chain 2. Slip stitch to the top of beginning chain 3. (Total of 24 double crochets, 8 chain 2 spaces.)
Rd. 3: Chain 3, 2 double crochets, chain 2, 3 double crochets into first corner, chain 2,* 3 double crochets into next space, chain 2, work corner (3double crochets, 2 chains, 3 double crochets), chain 2*. repeat from *-* 3 times. Slip stitch to top of chain at the beginning of the round. (Total of 36 double crochets and 12 chain 2 spaces.)
Continue in this pattern. With each consecutive round you should gain 1 double crochet cluster and 1 chain 2 space on each side of the square. (Adding a total of 12 double crochets and 4 chain 2 spaces in each round.) Hope this helps.