@ acano

If you are in the fields of mathematics, you probably don't need XeLaTeX since all the relevant symbols are already covered by standard LaTeX. But if you want to run XeLateX, the easiest way to do it from the debian image is probably to install texlive-xetex (by typing "apt-get install texlive-xetex" in the terminal). This should give you a working environment. I don't remember how much space you need, but I'm pretty sure there isn't enough space on the standard image, so you have to delete some other applications or increase the size of the image.

Best regards