Quick definition: definite articles means the article is definitely known. The cat, the girl. If it’s unknown (or indefinite) it’ll be a cat, a girl. That’s the difference between a and the.
In French these ‘articles’ must match the word’s gender. In most cases this is easy to tell, as words follow patterns based on their endings which you get used to over time. So don’t worry about getting it perfect at the start or it may become a distraction to the more essential aspects. But as a rule of thumb (with many exceptions), if the word ends with an ‘e’ it’s quite likely to be feminine.
-ette is a feminine ending, so the baguette in French is la baguette.
-ent is a masculine ending, so the president in French is le président.
To say there are several of either of those you say les (pron. lay): les baguettes and les présidents.
You may have noticed an added ‘s’ like we do for plurals in English (baguettes, presidents). This is also the case in French. There is an additional plural ending that’ll be explained in another article.
So to sum up, la is for feminine words and le is for masculine. Les is for more than one of any object.
Any questions, please use the comments below.

