The manual includes a section on checking your input connections. For example, a "No Reception" message for HDTV, UHF, or VHF will direct you to check your input ports.
The Humax HV10003 manual is a comprehensive guide that covers all aspects of the device. Here's an overview of the manual's contents:
Humax HV10003 Manual: Complete Setup, Troubleshooting, and Feature Guide