Having multiple credit cards open with no balance should not hurt your credit score but it's best to use at least a few of those credit cards and then pay off the balance on time to help build credit.
Having the multiple credit cards with no balance and not using them won't build your credit though so if you do have multiple credit cards with no balance on them it's best to use the credit cards some and then pay them off to keep your credit score built up.
If you don't plan to use those credit cards then it's best to cancel them because eventually if you keep the credit cards too long and do not use them then the credit cards will likely be closed by the credit card company.
So decide which credit cards you plan to use and keep then keep those and use them and then close the other credit cards if you don't plan to use them.