This early work by Mozart is a charming and simple piece, likely intended for educational purposes. It features a clear melody and basic harmonic progressions characteristic of the Classical era.
Focus on evenness of tone and clear articulation of the Alberti bass accompaniment.
Andante, KV 1a is rated Henle level 1 of 9 — beginner repertoire, roughly ABRSM grades 1–2. In the RCM system it corresponds to about level 1.
You should be comfortable at Henle level 1. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Andante, KV 1a lasts about 1.5 minutes.
Andante, KV 1a is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.