Go to Settings > Developer Options > USB Debugging . This allows ADB commands from your PC.
You need two distinct ZIP files stored on your device's internal storage or external SD card: android 7.0 custom rom zip file download
OmniROM was created by a team of developers who aimed to experiment with Android development and try new ideas. It is a feature-rich ROM that introduced several innovative concepts to the Android ecosystem, such as the "OmniSwitch" app switcher. While not as widely known as LineageOS, OmniROM offers a unique and highly functional experience for its supported devices. Go to Settings > Developer Options > USB Debugging