When to use what in Spanish?

well, i know you're interesting in learning english, right?

I thinks that's ok for u...

well i know haw to speack spanish beacus i'm peruvian, so i can speack spanish since I was a child.

iF you refers to a female concept u hav to use "la" for singular and "las" for plural form.

if you refers to male , u're using "le" singular and "les" for plural.

take some examples:

Ésto "les" pertenece.

Ellos le ayudaron a aprender español.... ==> "le" refers to the man who is learning spanish, he is unique

Ellos le ayudaron a apreneder ingles. ==> "les" refers to the group who is learning english. they are a group of males or maybe both men and woman.

Feminine usually ends with an "a" so you use "la", the plural form is "las".

Masculine usually ends with an "o" so you use "el", the plural form is "los".