Replicated first. Im very confused by it for some reason

As I am in the process of making the loading screen of my game I wish to load stuff in and what not, from what I’ve heard I should use ReplicatedFirst in order to load a bunch of stuff in thats in it, except Im just confused on what replicatedFirst (or as I will now call RF) works.
In the 3 years I’ve been doing this I have no idea what RF is and what it does and that sort of things so I would just like to know all that information.
And yes I did look at the doc.
And yes I had no idea what was going on there, so seeing people talk about it will probably help.

Thanks!

I recommend reading the documentation if you haven’t already done so. You can find the ReplicatedFirst documentation here.

ReplicatedFirst duplicates anything inside of it to the client before anything else. This is useful for local scripts that are essential for a game’s start, such as Loading screens, Guis, and tutorials.

Do note that these scripts will be cloned to the client before anything else, so you must wait for anything the scripts require.

ReplicatedFirst also provides access to the function ReplicatedFirst:RemoveDefaultLoadingScreen() which removes the default loading screen provided by Roblox. The default loading screen also removes itself after 5 seconds.