The Rolling Forecast Builder

Set up a rolling forecast for this business so we stop flying blind
between annual budgets.

Business: [DESCRIBE]
Horizon: [E.G. 12 MONTHS ROLLING]
Key drivers: [WHAT ACTUALLY MOVES REVENUE AND COST]
Data cadence available: [WEEKLY / MONTHLY]

Provide:
1. The handful of drivers the forecast should be built on (not every line)
2. A simple driver-based structure for revenue and cost
3. How to update it each period and re-extend the horizon
4. The variance signals that should trigger a re-forecast
5. How this differs from — and complements — the annual budget

Keep it lean enough that someone will actually maintain it.