Call to external libraries within Publishing

Hello there,

I am desperatly trying to use javascript external (i.e. not functions in a javascript code palette element) libraries (for instance jquery.js or underscore.js) in a Publishing template.
But I can't manage to get through!

My wish is to be able:
1°) Ideally to put a reference(same principle as in html pages, e.g. <script src="jquery-3.6.3.js"></script>) somewhere in Publishing document studio.
2°) if reference are not possible, what code structure to use for copying and pasting ? I tried to paste the code of the jquery-3.6.3.js file and it yielded errors.

Thanks in advance for your help.
Regards
Alioun