Your soundbar should have a pigtail with it. Each of the wires should be tagged for left front negative and positive, right front negative and positive, etc. If you connect them to the appropriate wires on the Jensen audio unit, then plug your television video and audio connectors into the back of the unit, you should get all your sound through the soundbar.
As for your existing speakers, simply cut the wires and tuck them up into the hole in the ceiling (or wall) and cover it with tape.
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