Kia ora Bruh
When you find it hard to identify language features, ones of the easiest things (I find) to do is to look at particular word choices, some interesting use of punctuation and sentence structures. You could even look at inverted order of words or cliches. These techniques will help you when it comes to non-fiction.
By finding examples of some of these, you can look at tone and then figure out the author’s opinion on the topic. In this particular piece, the writer is giving instructions and letting people know how they can access D&D. This would indicate that the writer holds a favourable opinion of D&D and is pleased about its shift from a subculture to more mainstream (the use of the word nerd in inverted commas)…hence the number of pop culture references. It is also indicated that this is part of people finding and exploring their passion and individuality.
One of the things about unfamiliar texts that is important to remember is that you just need to find small techniques to support your ideas. Get the ideas first and THEN find the evidence to support your ideas.