Just starting to read the series and the order is not so straight forward.

Apparently this is Asimov’s suggested order:

• The Complete Robot (1982) and/or I, Robot (1950)
• Caves of Steel (1954)
• The Naked Sun (1957)
• The Robots of Dawn (1983)
• Robots and Empire (1985)
• The Currents of Space (1952)
• The Stars, Like Dust (1951)
• Pebble in the Sky (1950)
• Prelude to Foundation (1988)
• Forward the Foundation (1993)
• Foundation (1951)
• Foundation and Empire (1952)
• Second Foundation (1953)
• Foundation’s Edge (1982)
• Foundation and Earth (1986)