Trying to learn basic coding stuff (super basic) for a class and I am a little lost.

SO the professor is very hands off and wants us to sort of wing it and learn on our own to a degree. Not asking anyone to do any work for me or anything. But if anyone is aware of some decent websites that offer some basic fundamental insight for using vim for html and css on a Mac, it would greatly appreciated. I am stumped at the moment on making a form in html for an assignment but I cannot figure out how to differentiate between different labels (as some are required fields, like when you fill out something on line and they have the asterisk by certain things like your name/email, etc). I have the required function correct but I cannot figure out how to set up a class target to differentiate between the fields that are "required" and are not (as the required fields need to be styled in red color text and the non required in black text). However, as it is now all of my fields are currently red. Is anyone aware of any youtube channels or sites that can provide some basic guidance?

I'm such a newb at it, that when I search things on the subject, most of it goes over my head and confuses me more. I appreciate any input and if this is a stupid question I apologize. Thanks baws.

Edit to clarify: I am using vim, as the class requires, on my Mac but I am pretty sure that this is not how real coders go about doing these things but I imagine the teacher is wanting us to use the bare minimum basic html/css in vim to help learn building blocks, and I am not sure if downloading a plugin or vscode would be out of the parameters of what we can use. (if that makes sense). Sorry, like I said I am a green horn at all of this but I am trying to learn as much as possible without having to try to use any additional software, so I can master this very basic lesson. I appreciate an input, especially from my TD brethren, as much of what I google leads me to things that are further confusing me and "over my head."