Your TV set hasn't got any dedicated audio outlets for a sound bar
https://www.manualslib.com/manual/650778/Panasonic-Viera-Tx-L32x5b.html?page=68#manual
so you'll either need to use an HDMI cable to connect to the soundbar or use the headphone output instead.
Not all sound bars have HDMI inputs, so you'll need to check whether your has or not. If it has, then simply connecting an HDMI lead between the relevant sockets might be all that you need to do. If there's no HDMI input on the sound bar (or using that connection doesn't work for you) you'll need to use a 3.5mm stereo jack-to-jack lead to connect between the headphone socket on your TV and the 3.5mm input on the soundbar. (I've never come across a soundbar that hasn't got such an input available). Discount stores often sell those leads for a pound or two. e.g.
https://www.wilko.com/en-uk/wilko-35mm-jack-to-jack-cable-1m/p/0342661
They're even cheaper online:
Amazon.co.uk User Recommendation
(If you do it that way though you'll need to go into the TV's menu settings to check that the headphone volume is set to a reasonable level).
If you need further help, please tell us the model number of the soundbar.