If you withdraw from a cl in college? ...?

So I just got an email from my university and it says that during your whole undergraduate career you can withdraw from a cl to a maximum of three times....what does that mean? I already got my midterm grades and I have an F in a few cles...does that mean that if I pick to withdraw from one of thsoe cles the grade won't count so it wont destroy my GPA but I still get the credits...or do I get no credits and no grade? A lil confused...I know its different from dropping a cl (which happens only a few weeks after the semester)...I have till friday to decide....any suggestions and what does it mean I still get the three credits for that cl!?