One of the key elements of fingerstyle guitar is the ability to use each of your fingers independently. This is especially important for the right thumb, as this finger plays the bass notes. The bass often leads the rhythm and groove of the music, which is why its coordination needs to be very steady.
The most important aspect of this exercise is to keep the beat constant. Repeat the fragment a couple of times while trying to keep the beat as steady as possible.
The two dots at the end of the transcription denote that the fragment is repeated.
Notice that the left index finger is used to fret the second note of the first bar. The reason for using the index finger instead of the middle finger is that it enables one to let the fragment its last note ring when the fragment is played repeatedly.