Resources for further reading:
First of all, a quick review. If you want to say that you are doing something, you will use a conjugated form of estar followed by the present participle of the verb (formed by adding –ando or -iendo).
I am walking = Estoy caminando
I am singing = Estoy cantando
I am eating = Estoy comiendo
Now, let's say that you want to talk about what you were doing in the past. Use the exact same format that you learned… except substitute an imperfect form of the verb estar for the present tense.
I was walking = Estaba caminando
I was singing = Estaba cantando
I was eating = Estaba comiendo
Why use the imperfect rather than the preterite? Because an action that is progressive is also continuous, and continuous actions require the imperfect.
Por ejemplo (for example):
Want to learn more about Spanish Tenses? Take a look at these lessons:
See you soon! ¡Hasta pronto!
Mauricio Evlampieff: Rocket Spanish