I am knitting a sock monkey and so far it’s going well! I have not finished one leg but it says now that i have to Break main color. Leave sts on contrast length of yarn. what does that mean I have to do ?
Understanding a pattern
If you have a pattern link when asking questions it would help us help you. 
This seems pretty clear though this time. Cut the yarn then take a yarn needle and a length of yarn that’s long enough not to pull out of the stitches and thread it through the stitches and remove the knitting needle. You’ll come back to those stitches later to finish that part later in the pattern.
Just to clarify, you don’t thread the yarn from cutting it through the sts, though I suppose you could. It will be easier to work on those sts later if you use another piece of yarn, or a stitch holder or other needle.
Yep, Sue is right. Use another piece of yarn. I also suggest a smooth lighter weight yarn. It’s easier to remove.