You plug the cable into the back of your Xbox 360, there should a be a switch on that says either "HDTV" or "TV" .. make sure it is switched to TV.
The numerous cables that come form it, most of them are for the HD tv, but there are three cables .... red, white & yellow.
In your box, there should be a SCART block, you put the red, white & yellow cables into the corresponding jacks.
Plug the scart into one of the spare AV sockets on the back of the TV.
Hopefully when you switch on the Xbox ... your TV will automatically switch to the right station & you will see & hear the picture.
Hopefully !!!