How to Crochet a Hat Using 100% Cotton Yarn

You’ll Need:
100g of yellow 100% cotton yarn;
Crochet hook 1.3 mm.
Head Circumference:
48 cm.
Instructions:
Make 4 chain stitches and circle them in the ring.
Row Details:
1st row: 9 double crochets in the ring;
2nd row: 2 double crochets in every stitch;
3rd row: *1 puff stitch, 3 chain stitches*; repeat from * to *;
4th row: *2 puff stitches in 1 arch of 3 chain stitches and 2 chain stitches between them, 2 double crochets in the next arch of 3 chain stitches*; repeat from * to *. You should get 9 gussets. Then, make 2 puff stitches, 2 chain stitches between them, and 2 chain stitches between puff stitches of the previous row. The quantity of stitches is the same. Increase the quantity of double crochets in the gussets by doubling the 2 central crochets;
5th row: 4 double crochets in 1 gusset;
6th row: 6 double crochets;
7th row: 8 double crochets;
8th row: 10 double crochets;
9th row: 12 double crochets;
10th row: 14 double crochets;
11th row: 16 double crochets;
12th row: 18 double crochets;
13th-16th rows: crochet straight without increases;
17th row: decrease the quantity of crochets in gussets by making 2 double crochets together before puff stitches and after them;
18th-19th rows: crochet straight without decreases;
20th row: decrease 2 double crochets as described below;
21st row: crochet straight without decreases;
22nd row: decrease 2 double crochets in every gusset;
23rd-24th rows: crochet straight without decreases;
25th row: decrease 2 double crochets in every gusset;
26th-28th rows: crochet straight without decreases. Then, make 7 rows of single crochets.
Please, please help me with this pattern. There are no instructions as to how to join; row 4 to end doesnt tell you exactly ow to do this pattern at all. Can you please give me a better understanding of this pattern. I love it, and have tried it three time, and it still doesn't look like it should.