Create a User Master for the Sales Representative

Menu Path: Operations > Masters > Users 

Assign the specific customer to the above user as Sales Rep

Menu Path: CRM > Masters > Customers > Select the customer > General tab > Sales Representative > Assign the user previously created

Settings for  Commission cost and Commission calculation

Menu Path: Admin > System settings > Business Rule settings > Sundry tab

Enter Cost for Commission Calculation and Calculate Commission On

Commission % in Product Master

Menu Path: Masters > Products > Select the Product > Product master > Sales tab

When Sales Transaction is created for this customer, the sales representative would be automatically linked to it.

Sales Rep can be changed while creating a Sales Transaction.

When the Product for which Commission % is set in Product Master is added in the Sales Transaction, the commission is added to the sales Representative and displayed in the Commissions by Sales Rep, Commissions Details, and Sales Commission Analysis Reports.

Commissions by Sales Rep Report

Menu Path: Go to Sales > Reports > Commission by Sale Rep

Commissions Details Report

Menu Path: Go to Finance > Reports > Commission Details

Sales Commission Analysis

Menu Path: Go to Finance> Reports> Sales Commission Analysis