Your manual for your TV is here:
http://www.m4c.magnavox.com/files/1/...f7_dfu_aen.pdf
On page 24, it tries to make the process painless.
7.2 Autoprogramming
This section describes how to search for and store
Channels automatically. Before you tune channels,
Ensure that you are registered with your cable
TV provider and that your equipment is correctly
Connected.
1. Press MENU on the remote control and select
Installation > Autoprogram > Start
Now.
Select Cable or Antenna and press .
• When Antenna is selected, the TV detects
Antenna signals. It searches for NTSC and
ATSC channels available in your area.
• When Cable is selected, the TV detects
Signals supplied by cable. It searches for
NTSC, ATSC, and QAM modulated channels
Available in your area.
3. Press OK to start the installation.
If you run Autoprogram when you have locked
Channels, a message appears asking to enter your
PIN code. Enter your PIN code in order to
Complete the installation.
If you have forgotten your PIN, reset it as
Described in Set or change your PIN on page 18.
When autoprogramming is complete,
This message appears “Channel search
Completed”.
4. Follow the on-screen instructions to complete
The installation.
You don't need a converter box. You will have to auto-program after the switch too.