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What TV do you have and what is the model number of the system?
Basically you need to see what inputs are on the cinema system and see if there is a matching output on the TV, i.e. if the cinema system has a optical input and the TV has an optical output you need an optical TOSlink lead to connect them. if there is only analogue inputs (phono/RCA connectors) on the cinema system and you have matching analogue outputs on the TV then you use them.
If you mainly watch your TV from an external source such as a sky box or freeview box, ect then you can also use the audio outputs on that box if the TV hasn't got a suitable audio output.