I'm using Small Basic, but there's a library that adds a ton of new features called LitDev.

I wanna use it, because it has a function that creates a matrix, which is a 2d array where values can be read and writed. I use it for the levels.

Because it's so useful to me, can i use it?

Yes.

Entrant is allowed to use library(or libraries).
Good luck to you!!!