We typically use "have" to express ownership, but in Spanish it expresses many different ideas.

Tener hambre - To “have hunger” / To be hungry

Tener sed - To “have thirst” / To be thirsty

Tener ganas de - To “have yearning for” / To be in the mood for 

Tener que (verb) - To “have to (do something)”

Remember, you still have to conjugate your verb to use these phrases!

Yo tengo hambre. - I am hungry.

Ella tiene que estudiar. - She has to study.

Nosotros tenemos ganas de comer pizza. - We are in the mood to eat pizza.