These etudes are designed for pedagogical purposes, offering a structured approach to developing piano technique. They often explore specific musical ideas or technical challenges within a clear framework.
Focus on achieving a smooth and even tone throughout the scalar and arpeggiated passages.
30 Progressive Etudes (WoO.37) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
30 Progressive Etudes (WoO.37) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.