Video - Galeri is a blg web site that have DIY videos
Started with 60 chains and an extension handrail woven into each chain
Make 5 rows of 5 different colors of baby wool and a crochet handrail. They stretched the handrail in each row by pulling it 2 times. After finishing all 5 rows, make a row of edge lace when it comes to the arms.
In the second row of edge lace, you need to jump evenly in the section where the arms will be. We continue knitting the rim cord like the other parts of the vest. When the vest has the proper paint, finish all the edges with a different edge lace with crochet.
If you measure according to your baby's neck while starting with a chain, I guess it can be exactly the right size for your baby.