Wht's a marker?

Hi …
I am in desperate need of help i got stuck in shape crown of a hat as i don’t understand wht this term means please explain as i am a begainner at this… :shrug:
Decrease Round: [K2tog, k to 2 sts before next marker, ssk] 4 times.
thank you…
Parnia :pout:

Someplace in the pattern they should have told you to PM–or place marker(s).

A marker can be a little plastic circle sold for that purpose, or you can just use a piece of yarn and tie a loop on the needle. It just helps you keep track of where you are in the pattern. When you get to a marker, you just slip it from one needle to the next.