جَاءَ زَيْدٌ وَقَامَ عَمْرٌو
Zayd came and ʿAmr stood up.
The conjunction joins two associated assertions. But adjacent sentences do not invariably require wāw. If the second clarifies or reinforces the first, or answers a question naturally raised by it, separation may be more effective.
Ask whether the second sentence contributes a new coordinated assertion, restates or explains the first, or functions as an answer to an implied question.