Could you clarify when to use the subjunctive? It seems to be used with the word "que", but not all the time? How do you identify when it is appropriate?

The use of subjunctive is quite complicated and not even mastered by most French people! So do not worry if it takes time to wrap your head around it. However it is very useful and allows to reach higher levels of complexity in your sentences. You can almost always use a simpler structure, but in some cases you will be required to use more complex forms. The most important thing to remember is that it is a mood and not a tense - there is present subjunctive, past subjunctive, imparfait subjunctive and plus-que-parfait subjunctive (the last two are not used a lot, it sounds a little bit old-fashioned). It is used to express something; doubt, fear, obligation, a wish, an opinion (very important), among others. Finally the most simple use is when "que" or one of its other forms (qui que, où que, quel que...) is the first word of the sentence.

Here are some examples where the first sentence is a clumsy or too long:

-Doubt : "Je ne sais pas si il a envie de venir" / "Je doute qu'il ait envie de venir"

-Fear: "Elle est peut-être trop timide pour me faire des amis" / "J'ai peur qu'elle soit trop timide pour me faire des amis"

-Obligation: "Tu devrais partir tout de suite" / "Il faut que tu partes tout de suite"

-Wish: "J'aurais préféré si l'examen était moins compliqué" / "J'aurais préféré que l'examen soit moins compliqué"

-Opinion: "J'aime comme il est impliqué pour cette cause" / "J'aime le fait qu'il soit si impliqué pour cette cause"