Hola Linda

I'm not 100% sure what the confusion is about. We have hints in some of the sentences instructing to use the Pretérito Perfecto, but we have given both options as correct "with the perfect and with the preterite" - is that part what you find confusing? 

Depending on being on a Latam focus or a Spain focus you use one or the other (generally one over the other but sometimes they are interchangeable), this is why we don't penalize the use of the other tense if you don't follow the hint. 

If you'd like to expand on this and show us more precisely what you found confusing, we can take your comment to Help Desk and use screenshots. Let us know if you'd like to do this.

Saludos cordiales 

Inma