Getting familiar with a huge project

Recently I got hired at a job which has a huge website, it uses bootstrap and a lot of custom Sass, while the classes aren’t informative nor there are any comments, It is hard for me to understand what and how to use and there is a lot of trial and error which is time-consuming.

So I wanted to know what is the best approach to get familiar with such a project?

Aren’t the classes bootstrap classes? Are you modifying an existing site or making a new one? You’re looking for an image and/or written documents describing what they want for a new one. If it already exists and you’re told what changes to make, look at the html and the compiled css and start making notes: what is creating the layout of the page, then color scheme and element styling, then typography ( text styling ). I assume you’ve done some training in each thing you’ve mentioned. Like FCC or something else? Do you have more details.