Mrs. Jennings' classes' webpage: The present progressive (ing)
The present progressive or "ing" like in "I'm writing" is formed in Spanish with the verb "estar (to be)" and with the ending "ando" for verbs that end in "ar" (like "hablar") and "iendo" for verbs that end in "er/ir" (like "comer" and "vivir").

For example:
I am talking.= Estoy hablando (I conjugated "estar" in "yo" form, and I took off the "ar" and added "ando" to the verb.)

She is swimming.=Está nadando.