These are short, contrapuntal pieces that serve as excellent introductions to Baroque polyphony and keyboard technique. They are characterized by their clarity, structure, and often charming melodic ideas.
Focus on developing independence of the hands and clear voicing of melodic lines.
18 Kleine Präludien is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 3.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
18 Kleine Präludien is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.