There are 4 "norrmal" quarter notes to the bar. When they are, as here, triplet quarter notes you need to fit 3 of them into the space of 2. If you have done 2v3 polyrhytms, you will know how that works. The strong beat is on the first quarter note (as marked) with a slightly weaker one on the fourth in the bar. The feel is ONE two three one two three.
The top line is four quarter notes, with each quarter note being "replaced" with a tripletised 8th note, so ONE two three, one two three, one two three, one two three.
You will see that the notes line up, but the accents mostly do not (they do at the start and again in the middle, but nowhere else). The challenge/purpose of the etude is to make sure that each line is correctly accented - ie, played with the correct rhythm.
And AJ is correct that the goal is to feel the two rhythms independently. And indeed, it is probably essential to do so.