What kind of hot sauce is that? Sounds like a generic term (a sauce with heat from spices or chillies/chiles), but I suspect it may mean something more specific in the West, because of this:
I eyeballed my brine solution and got mold growing on my chilis though, for what it's worth. I was roughly following youtube channel `Brother green eats` video [1]. I guess I should have followed more carefully.
[0] https://www.eater.com/2015/3/20/8253411/new-sriracha-chef-ho...
Ideally nobody is sticking up out of the water, as that's where mold will form. You can use a plate or some kind of weight, or stir it all once a day, or just let it sit and throw out anything that starts getting moldy.
Let this sit on the counter for a week or two until the brine and the peppers get sour from lactobacillic fermentation. It's up to you. When you like the taste, blend it all smooth and put it in a jar in the fridge. You'll get the same sour spiciness you're used to in hot sauce, but much more umami and depth in the flavors. Vinegar-based hot sauce is quite one-noted in comparison.
Note: I really recommend Katz's "Art of Fermentation" as a source of inspiration. I used to get annoyed by the fact that he doesn't actually give recipes, but have come to realize that you don't really need them. There are really only a few core processes with infinite variations, and precise measurements would most likely just lead you astray because you'll invariably need to respond to different produce and different temperatures.
Troubleshooting: Sometimes the brine starts to get cloudy, or a thin layer of surface yeasts forms. It's harmless but can lend a funk to the flavor. If you don't like this, change the conditions to select for the desired bacteria: make the brine saltier and/or keep it somewhere cooler. You can even keep it in the fridge, but then fermentation will be much slower. Also, sometimes the garlic turns blue. Also harmless.
Bonus: Sauerkraut couldn't be easier: Shred a bunch of cabbage (it's such a pleasure to use a mandoline for this) and add 1.5% salt by weight. Squeeze and knead the cabbage until it feels like wet laundry. Pack it into a jar; there should be enough liquid to submerge the cabbage. Again, find a way to keep it covered and wait 7-10 days. If you keep the brine from an old batch, you can dramatically speed up the next batch by mixing some in.