It should be relatively simple. Your TV should have a digital audio (optical) output port. Your Bose has a 3.5mm audio input (https/www.bose.com/en_us/support/article/connecting-an-external-audio-device0.html). So all you need to do is convert the digital audio to 3.5mm. Assuming of course you're talking about these speakers (https/www.bose.com/en_us/support/products/computer_speakers_support/companion-5-multimedia-speaker-system.html) and Bose doesn't have a different Companion 5 speaker system out there somewhere.
Step 1. Buy a convertor (I use this one https/www.amazon.com/PROZOR-Digital-Converter-Toslink-Adapter/dp/B00KNNSKV0/ref=sr_1_3?ie=UTF8&qid=1548384554&sr=8-3&keywords=optical+to+3.5)
Step 2. Buy either a 3.5mm to 3.5mm cable (https/www.amazon.com/AmazonBasics-3-5mm-Stereo-Audio-Cable/dp/B00NO73MUQ/ref=sr_1_4?ie=UTF8&qid=1548384687&sr=8-4&keywords=3.5mm+to+3.5mm+audio+cable) or a RCA to 3.5mm cable (https/www.amazon.com/AmazonBasics-3-5mm-2-Male-Adapter-Cable/dp/B01D5H8JW0/ref=sr_1_4?ie=UTF8&qid=1548384716&sr=8-4&keywords=3.5mm%2Bto%2BRCA&th=1) your choice. Pick a suitable length.
Step 3. Connect the optical cable (included with the convertor) to the TV and the convertor.
Step 4. Connect the power to the convertor. If your TV doesn't have a USB port to power it, you'll need a USB power plug (https/www.amazon.com/Certified-Charger-Universal-Portable-Adapter/dp/B017TXGM4I/ref=pd_bxgy_23_img_3/131-1277966-4088503?_encoding=UTF8&pd_rd_i=B017TXGM4I&pd_rd_r=d21ddfdd-204b-11e9-b1bf-7d7bb058b622&pd_rd_w=3r6Wq&pd_rd_wg=0gej5&pf_rd_p=3f9889ac-6c45-46e8-b515-3af650557207&pf_rd_r=RASD0X4Q9H5465KR1QGX&psc=1&refRID=RASD0X4Q9H5465KR1QGX)
Step 5. Plug the 3.5mm to 3.5mm or RCA to 3.5mm cable in to your Bose system.
Step 6. Adjust your TVs audio to go through the digital out. The owners manual will tell you. If you don't have it, either look up the model online or get familiar with your TVs controls.