How do I access the chunks of a Custom Dimension?

[ignatux]

I am aware that the custom dimension is saved as a datapack, whenever I enter that dimension via the command

"/execute in minecraft:[dimensionexample] run tp [playername] [coordinates]"

It loads an empty void with a few floating villages and none of the saved chunks at all, I have no idea if this is a bug or not so I am placing this as a question for the moment so I think I might've missed a step or two. Any feedback is greatly appreciated!