We use the PROGRESIVO when we talk about actions IN PROGRESS. Of all verb tenses, this may be the one most often misused.
El progresivo has TWO parts: the verb ESTAR + el PARTICIPIO PRESENTE or the -ING form. This is sometimes called the GERUNDIO. What you've used with present/past perfect was the past participle.)
I am writing this explanation. (It’s what I’m doing right now.)
Yo estoy escribiendo esta explicación.
Yesterday I was cooking in the afternoon. (I’m talking about the time when I was actually doing it.)
Ayer yo estaba cocinando por la tarde.
Paso 1: Conjugate estar in the necessary form. You are going to use the present indicative if it's happening in the present, and you'll use the imperfect if it was happening in the past.
Paso 2: Form the participle:
The ending of a present participle DOES NOT CHANGE. It’s not an adjective. Do not change the ending!
El progresivo can only be used to talk about something in process - either in the present or in the past. It cannot signal something in the future.
In English, I can say: “I am eating with my family later today.” Or “We’re meeting at the park tomorrow.”
These sentences don't talk about something that is in progress. They talk about something that is going to happen in the future. We CANNOT use a progressive tense. WE have to use the future construction such as:
Yo voy a comer con mi familia más tarde hoy. Vamos a reunirnos en el parque mañana.
Remember.... Only use a progressive tense when you're talking about something in progress. Otherwise, the regular present tense, ir + a + verb construction, or the imperfect tense are more appropriate.