What do you need to record TV shows from the TV?

A video recorder, a recordable DVD machine or computer.

Most commercially available recorders have a tuner built in, so you can select the channel and record it.

Most modern TV's have an output socket in the form of RCA sockets, SCART or HDMI.

Match the correct sockets with those on the recorder with suitable patch leads.

Set the recorder to input from the correct socket and hit record.

Computers need a video capture card or device or a TV tuner dongle. Software is normally supplied.