Differently than many other sonatas by Scarlatti, this short but cheerful Minuet doesn’t present any particular problem in being transcribed and played on guitar. The original tonality of G major fits perfectly on our instrument. The use of the double scordatura (G and D in the basses) has been suggested to me by a natural harmonics effect which is possible to achieve thanks to that. It recalls a carillon and it sounds really nice!
 
It is a very simple sonata (harmonically and melodically), but yet, the bare of writing should not deceive us. On the contrary, it should inspire the player to improvise grace notes and vary the melody, having through this an active part in the compositional process. I wrote down in the score my ornamentation, but please, consider it only as one of the possible way to decorate, the goal is to encourage you to find your own.
Last but not least, I took the freedom to indicate the change of tempo from 3/4 + 3/4 bar group to 2/4 x 3, which is one of the most typical characteristics of the Minuet (hemiola).

I wish you lots of joyful moments with the K.391!