Grammar
French articles: le, la, les, un, une, des
English has articles, but not the same ones, and it has nothing like the French partitive. French makes you choose before you even name the thing. Three decisions cover most of what you need.
Definite or indefinite
le, la, les point to something both speakers already have in mind. un, une, des introduce something new or unspecified. Learn the gender together with the word, never separately.
Je cherche un hôtel.
I am looking for a hotel, any hotel.
L'hôtel est en face de la gare.
The hotel is opposite the station, the one we mean.
The partitive: du, de la, des
Before an uncounted quantity, French does not say « je bois café » but « je bois du café ». The partitive is required, including where English would say nothing at all.
Je voudrais du pain, s'il vous plaît.
I would like some bread, please.
Elle boit de l'eau.
She is drinking water.
After a negation
After a negation, un, une, du, de la and des all become de. The definite article does not change, and the contrast changes the meaning.
Je ne bois pas de café.
I do not drink coffee, none of it.
Je n'aime pas le café.
I do not like coffee, the thing itself.