1) install a screen capture app...
Debut screen capture is intuitive and the free trial should last longer than the tournament. No annoying watermarks or anything like that. You can learn all you need to know in a few minutes. Here you go:
https://www.nchsoftware.com/capture...UYxGWt_zWmct9MSuMtHKNjCwwB5YLOZJ2e1qPo7Sx8ndb
2) disable any power saving for the night
3) make sure you have enough storage for a few hours
4) depending upon the preferences in your capture program, check that audio record is enabled and make stream browser window full screen. Move your cursor out of the way and disable any screen savers.
5) start your stream as early as you can and go to bed :-)
Not ideal, but a workaround. Good luck with it