There are two common methods for hand knitting Bat Shirts: crochet and needle knitting. Crocheting is a method of crochet jacquard, and the things woven are flexible and diverse. Knitting is a common way for us to knit sweaters. Bat shirts can be woven directly into a whole barrel, or the front and back pieces can be woven separately and then put together, or they can be put together in several pieces. This is a bit difficult, and beginners can't finish it because they need a little clothing foundation. Starting from the bottom up, according to the established size, it is best to ask experienced people to help lift the needles, because they are more experienced in lifting as many needles as possible, and then add needles continuously on a regular basis. Short sleeves are relatively simple, just add needles according to the size and leave the cuff position. For long sleeves, knit to a certain length and measure the sleeve length. If it is a weaving program, it is similar, but it is simpler. This is a special machine, and people can do it specially. If you want to be more detailed and diverse, you'd better find and write such a book for reference.