Samuel James Berkahn's "2 Duets" are likely didactic pieces intended for beginner or early intermediate pianists. They would typically feature straightforward melodies and harmonic structures suitable for developing ensemble skills.
Focus on accurate rhythm and a smooth blend of sounds between the two players.
2 Duets is rated Henle level 2 of 9 — beginner repertoire, roughly ABRSM grades 2–3. In the RCM system it corresponds to about level 2.
You should be comfortable at Henle level 2 — meaning you can already play level 1–2 pieces cleanly. 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 2 Duets lasts about 6 minutes.
2 Duets is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.