"Simple" does not mean "Easy".
Others have pointed out some of the things the first study is trying to teach you. Each of these studies has its own challenges both musically and with regard to technique. If your right hand balance was good to start with, you might not find that part of estudio I so challenging. As was pointed out, part of that right hand control is bringing out the melody, and observing the dynamics and other markings noted on the score.
My first teacher was kind of crazy...he gave me the first ten in order. One per week. That was just to learn the notes, for the most part. That did not mean I "mastered" them and could play them flawlessly. It only meant I could get through them. I played those ten studies every day for three years. As time went on, I understood more about what each study was teaching.
In no way would I recommend that you follow that schedule of one per week. I think he asked me for one per week to see if I could do it.
Sure. I could do it. That doesn't mean it was the most efficient use of time or the most useful progression pedagogically.
Other teachers have mentioned that doing them in order is not what they would do if they were starting a beginner on them. Sorry I can't remember at this point what that order would be, but some of the teachers here might chime in with their opinions on that.
When the sun shines, bask.
Classical Guitar forever!