A very general guideline: you can wash everything on normal. Wool, rayon, foil/hologram, swim fabric, and bamboo should be hung to dry.
Which stitch should I use?
The stitches circled in green are your best options for sewing knits. If your machine doesn’t have these options, the ones circles in yellow will work, but are not ideal, and you may not be happy with the results.
Set your tension lower, and your stitch length longer. For example, if your tension settings go from 1-9, choose 3. If your standard stitch length is 2.5, lengthen it to 3 or 3.5. Check your sewing machine manual to see how to do that on your machine.
Which needle should I use?
For knit fabric, you want to use stretch or jersey/
ballpoint needles. They are designed to go between the
threads of the fabric instead of piercing them, which would leave a hole.
Stretch needles are best for fabric with
more spandex content (5% or more), and ballpoint/jersey are good for little or no spandex. Stretch 75/11 are a great all around needle for knits.