From that article:
Log In to Parts Tech
If you don't already have an account with Partstech, go to PartsTech.com to get started. You will need to set up available vendors on PartsTech directly; if you don't know what PT vendors are near you or supported nationwide, contact them through their application or call 866-308-5193.
Look Up Your API Information
While logged into PartsTech, navigate to your account by clicking on your account name in the drop down menu. When the drop down menu appears, click on My Account.
When your Account page appears, locate Settings in the navigation bar.
Click on or hover your cursor on Settings to reveal the API tab.
Click on the API tab and it will provide the credentials (login and password) you will need to enter into Shop-Ware.
Find the vendor on your Shop-Ware Vendors page that integrates with PartsTech. When you find the vendor on the list, click on it. On the far right of the vendor info, you will see a pencil icon. Click on the icon to edit the vendor information.
In the Add/Edit Vendor window, you'll see an Integrator drop down menu. Set it to PartsTech.
Enter your account credentials "Login" and "Password" (as shown above).
Click Save Vendor once you have entered your credentials. Now your PartsTech vendor integration has been made!
Order Parts Through PartsTech
Once PartsTech credentials are associated with a vendor, whenever you create a new order for that vendor on Shop-Ware, PartsTech will automatically launch and host a session for the order (or quote). It will also launch whenever you select eCommerce when ordering parts.
PartsTech combines all of its vendors into one session. This allows you to purchase across multiple vendors in one place at the same time.
Once you've finished shopping on PartsTech, you can send the parts information back to Shop-Ware as either a "Quote" or an "Order."
If you place an order, Shop-Ware will create the associated Purchase Order automatically.
If you place an order from a new Vendor, Shop-Ware will create the new vendor automatically.