Login with your account at cPanel site
Visit your cPanel site, you will se one icon on the top right menu. Click menu Profile.\

In Your Profile page, you can see tab Device, and then you can see button "Link Device". After clicking on this button you will see 6-digit OTP code, or QR Code.

Enter OTP Code or scan QR code
Come back to your Agent app, with Welcome page, you can see 2 button: Continue (Pair Device) and Continue without pairing. Click the first button Continue (Pair Device) you will see methods to pair your device (already installed the Agent app) with your account (already you login at cPanel).

you can enter 6-digit code and touch "Pair now"
or you can scan QR code by touching "Scan QR..."

After you see a successful message, your device (with the Agent app installed) and your account are paired (linked) together.