Direct object pronouns can be used to replace direct object nouns to reduce repetition. It would be like saying it, him, her, them in English.

In Spanish they must agree with the noun they are replacing.

After replacing the direct object noun with a pronoun, be sure to place it before the conjugated verb.

Here is the conversation all together.

las flores

Las flores

las

me

te

lo

los

nos

os

la

las

d.o.

Place d.o. pronoun BEFORE the verb

las

tengo

las

los platos sucios

d.o.

Los platos sucios

los

me

te

lo

los

nos

os

la

las

los

los

lavo

Place d.o. pronoun BEFORE the verb

Direct objects receive the action of the verb, or answer the question what or whom after the verb.

Sí, yo las tengo.

Yes, I have the FLOWERS.

Yes, I have THEM.

No, I am not washing THEM.

No, no los lavo. ¡Estoy estudiando!

No, I am not washing THE DIRTY DISHES.