The opening three bars represent few technical difficulties in terms of LH fingering. The main focus should be on getting the melody line, top notes, to ring clear of the chordal notes, and the same for the bass notes. From a harmony point of view, and this is important as it comes up again, it is an E minor chord (i) followed by a F#7 (or V of V), and B7 (V).
After these three opening bars Villa-Lobos moves up into fret VII via a series of min 6th chord shapes, shifted up chromatically (bar 4). Bar 5 is where it gets a little finicky from a fingering perspective. It is a little bit of a tight squeeze but based on guide fingers, this fingering solution is the best for these notes. So main points here are:
Barre Chord Refresher
As there will be a lot of barre chord work here in this study, just a quick refresher on how to achieve clarity with this technique, without hurting your LH. Top tips for clean, buzz free barre chords are:
Villa-Lobos has purposefully left the harmony hanging on a B7 chord in bar 5, as he intends to head back to Em (i), with a twist. He uses his signature move, shifting harmony over a static note. Which we will see in the next micro study.