How do I set who approves what?

In Settings → Approval rules. Each rule is a tier: who approves (such as a business unit head or the founder) and the amounts it covers, for every category or one. Margin starts with two tiers: ₹25,000 to ₹2,00,000 approved by an admin, leadership or a manager, and above ₹2,00,000 by an admin.