PL/1 syntax highlighting and emacs syntax highlighting in general

[Svet]

Hello,

I'm pretty new using emacs. I'd like to use it to work with PL/1 code,
but it doesn't seem to support syntax highlighting out of the box.
Does anyone know of  an existing pl/1 extension I could use? Or do you
know of a good guide(or examples) for writing my own extension for
syntax highlighting?

Thank you for the help!