Newbie Questions?

Hey, Warzone! Welcome to Rising World.

I'm probably the wrong person to answer all of your questions about mods, but I think I can clear some of this up for you.

So right now the only "mods" for rising world are actually Lua scripts. There's a whole section of the forums dedicated to it here: Lua Scripting

It's my understanding that Lua scripting is on it's way out because the next Rising World update is going to incorporate a new Plugin API that uses (I THINK) Java. People are discussing that over here: Plugin Discussion

There is no release date for the new update but Red (the lead Rising World dev) has already put out a "pre-version" of the new API for people to play with. However, if you wanted any kind of plugins today you would be limited to the Lua scripts currently available. These can be fun and helpful but don't add much in the way of UI changes.

Anyway, I'm sure I made the pros here cringe enough with my lack of knowledge, so I'll step aside now. Have fun with Rising World!! You're here at a very interesting time for the game.

Basically @Vortac has said everything that needs to be said The Lua API will be discarded in a few weeks, so of course you can still use the existing scripts until then, but if you decide to learn Lua in order to create your own scripts, I'd recommend to wait for the upcoming Java Plugin API instead. In will be ready very soon, and there is already - as @Vortac mentioned - a "pre-release" available.
The new API allows you to create plugins for the game, this is like "serverside gamemodes": A plugin can take control over the gameplay (or more precisely, the gameflow), so if something happens in the world, it can react on it accordingly (example: if a player hits another player, a plugin could either cancel this event [so nothing happens, the player does not get hit], or increase the amount of damage that will be dealt, or even apply the damage to the other player). A plugin is also able to manipulate the gameplay and the environment, i.e. it can move players, spawn items, modify the terrain etc. In addition, the API allows you to load custom 3d models into the game world (later this will by expanded, so you can create custom objects/items, add new recipes, load your own sounds etc).
You can also consider a plugin as a "lite" version of a mod. Biggest advantage of a plugin (compared to a regular mod) is the fact, that updates of the game will not (or only in very rare situations) break any existing plugins, and that - in multiplayer - the player doesn't have to manually download a plugin, it will be executed on the server, and every asset that's required (custom models etc) will be downloaded automatically.

If you decide to create your own plugins, you can already try it out or check out the documentation: https://javadoc.rising-world.net/
Or alternatively have a look at this topic, although it only gives a brief introduction: Create a Plugin
Although it requires some basic programming knowledge (otherwise it will be a rough road). However, once the API is fully released, and full examples are available, it will be easier to learn anything about the API