Question

how do we know where to use articles a,an and the

Answer 1

When u see the first letter 'consonant' then u take the use of 'a'.
When u see the first letter start with 'vowel' tgen u take the use of 'an'.
'the' is used when we talk about certain thing.
Hope it helps

Answer 2

1. Article 'a' :- used for a singular thing
For example- I was playing a game.

2. Article 'an' :- used before the words beginning with vowels
For example- I have an umbrella.

3. Article 'the' :- used before a specific word or the highest degree 
For example- She is the cutest.

Hope this helps you!