Turn a campaign goal into a full creative and channel brief

I need a campaign brief for this goal: Get 200 qualified demo signups for our new expense-management SaaS in Q3.
Budget: ₹4,50,000 for the quarter across all paid channels.
Audience: Finance managers at 50-500 employee companies in India.
Timeline: 8 weeks, launching September 1.
Constraints: No influencer spend; must stay compliant with RBI advertising guidelines for fintech-adjacent claims.

Write a one-page campaign brief with these sections:
1. Objective — restate the goal as a single measurable outcome
2. Audience — 2-3 sentences plus the single biggest objection this audience has before converting
3. Core message — one sentence the whole campaign should communicate, and why it's the right one for this audience
4. Channel mix — recommend which channels to prioritize given the budget and timeline, with a rough percentage split
5. Success metrics — the 2-3 numbers that would tell us this worked, distinct from vanity metrics like impressions
6. Risks — 2 things most likely to make this underperform, and what to watch for early

Keep it to something a media buyer or designer could read in 5 minutes and start working from. Do not invent statistics or benchmark numbers you don't have — if a number depends on data I haven't given you, say what you'd need instead of guessing one.