First the good news:There are only three articles in English: a, an and the.
There are two types of articles indefinite ‘a‘ and ‘an’ or definite ‘the’. You also need to know when not to use an article.
The bad news is that their proper use is complex, especially when you get into the advanced use of English. Quite often you have to work it out by what sounds right, which can be frustrating for a learner.