trying to download apps, i get error says. this apple id has not yet been used in the itunes store

You may need to be signed in (to the device you are using) with your Apple ID:

Sign in with your Apple ID - Apple Support

Also:

Apple requires you to have a payment method listed in your Apple ID account for the first time you use the App Store or iTunes., even if you only download free apps.

Check the payment methods that you can use with your Apple ID:

(Scroll down in the article below to find your country or region)

Payment methods that you can use with your Apple ID - Apple Support

How to: Change, add, or remove Apple ID payment methods - Apple Support

All the best :-)

When you get that message on your screen, tap Review to sign in, then review your account information.

Click Review repeatedly. 

Some people have only had a response after a second or subsequent click.

Try to download a free app at the App Store.

For example try to download this (is an free app).

Log in at appleid.apple.com and make sure you have payment information stored there.