Add a stitch at the end of each row, so repeat the knitting. When the number of stitches is increased to 10, add two stitches at the end of a line. This * * * counts as 12 stitches. (The last two stitches are the front edge of the vest) Then knit another stitch in the same way.
Add a knitted back at the other end of the front and add 18-20 stitches. Then connect the left and right pieces to continue knitting.
When knitting to the chest, you can accept the size of the collar according to your own preferences. Here, you can take one stitch on both sides every 3-5 rows, and then take one or two stitches on both sides to the width of the collar when knitting to the upper part.
When knitting under the armpit at the same time, leave 3 stitches on both sides, and knit the front and back pieces to the front and back collar respectively.
The front and back panels can be knitted to shoulder height. Then pick up the edges of the two sleeves and knit them.