I want to use the loader but I can't figure it out. Is it even able to be used on a browser?
It's possible, but we don't recommend it. Depending on your browser, it may require filepath whitelisting, plugin downgrades, security overrides, etc. And the technical problems will get
worse over time as Flash support is increasingly phased out.
It's much simpler to use the standalone
Flash Player projector tool instead.
If you download one of the common Loader packs (such as the one prepared by
sby) then you'll automatically get a copy of the Flash Player projector tool, along with a straightforward
"play sdt loader" shortcut (which you can simply double-click).
If you're still having difficulties, or if you'd like to learn more about how to acquire and use mods, then I would encourage you to read the
Newbie Guide.