The recording action is simple; put a suitable tape in, make sure its rewound to the start or where you want to add a new recording, then press record (or record + play, possibly, with some machines).
The harder part nowadays is finding anything suitable to record from.
A typical analog VCR can only record from either:
An analog broast TV signal, if it had a built-in tuner - but analog stations have stopped broadcasting.
A composite video input from another piece of old analog video equipment.
The only thing I can think of offhand that you are likely to be able to get as a compatible video source is something like an older video game console that has AV out on phono plugs.
No newer digital video equipment is likely to be compatible in any way with the type of input signal an old VCR needs.
To make a copy of a tape you would need two good working VCRs and connect the audio & video outputs from one (playback) to the audio & video in of the other (record).
Start the record machine and give it a few seconds to get past the tape leader, then start the playback one.