Add or create new purchase order?
For creating new purchase order you have to follow to Steps:
Step 1 - Create a Client
Step 2 - Create a purchase order
Step:1 Create a client
1. Go to Clients tab
2. Click "New Client"
3. Fill in the form (email address is the only required field)
4. Click "Save"
Step :2 Create a Purchase Order
1. Go to "Purchase Orders"tab
2. Click "New Purchase Order"
3. Select your client:
4. Add purchase order items as required:
5. Click "Save"
Source: http://fetchflow.com/support/question/How-do-I-create-a-new-purchase-order.html