Switch it on. Open Settings → Modules, find Partner Management and enable it. Vendors → Partners appears in the menu.
Create your tiers first. Open the Tiers tab and click New Tier for each level (see Tier system). For example:
Silver: 5% commission, from ₹0;
Gold: 8% commission, from ₹1,00,000 in sales;
Platinum: 10% commission, from ₹5,00,000 in sales.
Add partners. On the Partners tab click New Partner. Enter the Name and a Partner Code (short and unique, for example PRIYA10), plus email, phone, website and tier.
Give each partner a coupon. In Marketing → Promotions, create a coupon with the same code as their partner code. This is how you'll see which orders they brought in, because orders are not linked to partners automatically yet.
Each month, look at the orders that used each partner's coupon, work out the commission, and pay the partner yourself (UPI or bank transfer).