My iCloud is not connected to my App Store and I can’t download any apps

Unfortunately this is a long list of things to check but you have provided too little information for us to propose a specific solution. Describing what happens when you try, and the exact wording of any error messages, would greatly aid us in helping you. In the meantime review these suggestions and documents if you think they apply:

If you can't connect or sign in to iCloud, see if this document has a solution --> If you can't connect or sign in to iCloud - Apple Support

Read this document if you can’t download or update apps on your iPhone or iPad --> If you can’t download or update apps on your iPhone or iPad - Apple Support

If the first 5 don't help, use the 6th.

If you see a message that says "Your account has been disabled in the App Store and iTunes", follow the directions in this document --> If a message says 'Your account has been disabled in the App Store and iTunes' - Apple Support