1. We prepare the yarn and knitting needles for knitting. Let's do a knitting demonstration with 18 stitches.

2. We knit from top to bottom, starting with the collar, knitting one stitch down and one stitch up on both sides; after knitting to the length of the collar, change to knitting down and knitting up on the back. Then knit 2 stitches on the left and right sides of the edge, and knit them on both sides.

3. After the collar is knitted, change the needle method and start adding stitches in 4 places; 18 stitches on one, add one stitch to the left and right of the 3rd, 6th, 13th, and 16th stitches, and then add once every other row until the required size is reached. Knit the two stitches on the left and right sides of the edge as before, so that the edge will not curl up.

4. Next, tidy up the fabric and thread the sleeves with the thread ends for later use.

5. Then start knitting the body part, and knit the lower stitches on the front side and the upper stitches on the back side.

6. After knitting to the required length, change to upper and lower stitches, knit the edge of the sweater, and cut off the thread when it reaches the required length and thickness, and hide the thread ends.

7. Next, we start knitting the sleeves of the sweater. Put the coils of the sleeves on 3 knitting needles respectively, start knitting the lower stitches, and knit the cuffs under the armpits according to the required sleeve size. Knit to the required length, and then use upper and lower stitches to knit the cuffs.

8. Use the same method to knit the other sleeve. After knitting, cut off the thread and hide the thread ends, and tidy it up. In this way, the cardigan knitted from top to bottom is completed.