As a beginner, How should I learn how to write java code relevant to the Unity Engine?

I know there are certain universal standard buttons, and i’m looking for a way to learn all of that and the common phrasing such as “transform” etc.

Java does not exist in the Unity Engine.
However, if you mean JavaScript, you could take a look at the Script Reference.

My method of learning is, don’t learn, until you really need it.
Why? Because it’s quite simple!
You will never learn Scripting/Coding/Programming/etc., if you read everything at once, you have to actually apply it, in order to learn it.

For example:
I know how to use Transforms? I’ll just use it.
But how do I rotate something? Google “Unity rotate”. Alright, so I’ll use “transform.Rotate”. How does it actually work? Let’s try it in my game! Wow, it works! Skills gained.

I do this all the time, and as a result, I became a very decent Unity C# Scripter.
JavaScript works the same way: Get stuck, research, apply what you just discovered, learnt!