of the device you are trying to upgrade? Knowing this will allow for checking if an Android 7.0 custom ROM actually exists for it.
Upgrading from 4.2.2 to 7.0 is not an over-the-air (OTA) update. It’s a surgical operation. Prepare these items:
If you see a bootloop (repeating animation for >30 minutes), return to TWRP and perform a again. If that fails, you selected the wrong ROM architecture (e.g., ARM64 on an ARMv7 device).