There are things that I still do not know how to do, and if looking for it on the internet there is someone who has already done a script I can use it. Or do I write everything by hand based on it? PD: It is my first Jam
Everyone has to google everything, even advanced programmers, so you don't have to worry about that. But just copying what you see on the internet is a really bad practice. No one is preventing you from doing it, but you should really try to write your own code based on it instead, that's the best way to learn and improve.
You can make glow effects VERY easily with Shader Graph if you're using Unity 2019.1 or 2019.2. There are lots of good YouTube videos introducing you to using Shader Graph. You might need to switch to the Low-def render pipeline, which might mean you have to change some existing shades because the default 3D standard shader doesn't work with LDRP.
We all use examples to learn. As long as you're not straight up copying a bunch of someone else's code I think you're fine. We're all here to share and grow as devs. You'll definitely want to finish this jam knowing YOU made something. It will be so much more fulfilling if the thing you submit is yours.