Spanish Language Question

A year and a half of Duolingo and some actual classes and I've got to a bit that I'm confused about.

I used to play.

I played.

Both appear to be Yo jugaba.

Eg:

De niño, yo jugaba en el campo.

As a child, I used to play in the field.

Yo jugaba en el campo.

I played in a field or I used to play in a field?

The aba, abamos, aban endings etc are confusing me.

Or is it just my dependency on DuoLingo.

Gracias.