تَفَقَّدَ الْأَمِينُ الْأَوْرَاقَ فَوَجَدَ بَعْضَهَا تَالِفًا.
The custodian inspected the leaves and then found some damaged.
Fāʾ portrays inspection and discovery as closely linked successive stages. Wāw would coordinate the actions without itself specifying such sequence; thumma can highlight a more separated progression.
These particles should not be treated as precise clocks. Their conventional discourse meanings interact with the described events and the wider context. The important comparison is what each connective explicitly contributes.