There’s no way to do this without purchasing other Sonos hardware. If watching video on the PC, I would look at a Sonos HT Soundbar instead, perhaps with either HDMI-ARC, or Optical output, but it depends on the available connections on your PC - If your only option is ‘Bluetooth’ audio-out, then you’re going to need a Sonos product with a BT Rx, such as Era-100/300, Sonos Roam, or a Move 2 (now on pre-order). I would give the Move (gen1) a miss, as it’s BT link cannot be shared with other speakers, like your Sonos One SL.