Tweak UI: Does it apply ALL the settings, or just the current ones?

I have an OLD system, and I’ve looked at the Microsoft program Tweak UI several times over the years, but I’ve never actually had the courage to use it. The reason for that is that there are no instructions for its use, so I don’t know:

  1. If I change a setting and click the Apply button, is it just going to apply the settings in the currently selected section, or will it apply ALL the settings from ALL the sections?

  2. If it applies all the settings, when Tweak UI loads, do all the settings reflect the current state of my system? In other words, if I change one thing and click Apply, will it ONLY change that one thing because everything else will stay set the same way it was?

I’m leery of using it to make any changes because I don’t want it to accidentally change something else just because Tweak UI came up with a setting that differed from how it’s currently set on my system.