As monchavo said, I wouldn't worry about using one speaker. My advice is to try it out and if want something more you can always buy a 2nd speaker later.

Cables

For mic cables I've used these, they work well and you can get them in various lengths.

https://www.amazon.com/Cable-Matters-2-Pack-Microphone-Feet/dp/B00KO8VZ3E/ref=sr_1_3_sspa?crid=2Q6W8HY6C3EM6&dchild=1&keywords=xlr%2Bcables&qid=1617881663&s=musical-instruments&sprefix=xlr%2B%2Cmi%2C184&sr=1-3-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzMEZIM1FMU0szRlBFJmVuY3J5cHRlZElkPUEwMjQ2MjY0MjA5U0pPTVhVTzJKSiZlbmNyeXB0ZWRBZElkPUEwMDE0MzExMlVUSTIxUTVRVktPNyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

From the L R Main Outs on the mixer to the line inputs on the speaker you need something like this. There are others on Amazon if you need it longer.

https://www.amazon.com/Hosa-CPR-202-Stereo-Interconnect-Meters/dp/B000068O17/ref=psdc_3236443011_t1_B000068O16

From the laptop to the mixer I would use this from the headphone jack on the laptop to the channels 11/12 inputs on the mixer

https://www.amazon.com/Cable-Matters-3-5mm-6-35mm-Breakout/dp/B07PJTP7DR/ref=sr_1_1_sspa?crid=2Y03VIPITXW&dchild=1&keywords=3.5mm+to+dual+1%2F4&qid=1617882914&s=musical-instruments&sprefix=3.5mm+to+%2Cmi%2C164&sr=1-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFZNlBFSlM0SEQyN0gmZW5jcnlwdGVkSWQ9QTA3NTUyODE3VTA3V1hOOUlETjkmZW5jcnlwdGVkQWRJZD1BMDY1NTg2NzFOMk5ORUdGSUlOTlYmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl