In home page, Select Purchases. Second menu is Create Purchase order.

This page helps you to create the orders to be purchased.

To the left side of your page you have an option to Add the vendor.

Then fix the Gold rate and Click on Products. 

The following table will display.

Enter the details of order to be purchase and Click on Create, the table will get filled

To Add further Products

Click on Products and follow the same procedure, the table will display as shown below.

Then Click on Place order in the bill.

You will get a notification on the page

To Update the details of Ordered product