You can use article such as a and an before countable nouns
Be careful, you can not use countable nouns without article (a/an). 

(ex) I want to eat an apple.
(ex) Eastern people usually eat rice every day.

There are singular countable nouns and plural countable nouns in countable nouns.
You can use singular countable nouns with a/an
You can use plural countable nouns alone

(ex) She is a Monash language centre student.
(ex) There are many students in Monash language centre.

You can use some and any with countable nouns.
You can use some and any With plural countable nouns...

(ex) He sang some songs yesterday.
(ex) Did you buy any bananas?