If you haven't already, sign up for a free EasyPost account by following the steps on their site.

Set up a primary payment method and recharge plan on the Billing page. EasyPost charges no flat or monthly fees.

Once logged in to your EasyPost account, go to the Carrier Accounts page.

In the "Add Carrier Account" list, find (or filter by name for) the "UPS" option and select it.

In the "Add Your UPS Account" that appears, fill in your account information using the info provided by a recent UPS invoice:

Once your UPS account is connected to EasyPost, go to the API Keys page.

Copy (or create)  Production API Key for use in SKULabs. Treat your API key like a password. it shouldn't be made public on your website or included in emails.

Log into SKULabs and go to the Add a Shipping Provider page.

Select UPS from the carriers list and paste your Production API Key into the "EasyPost API Key" field. The dropdown field below should update with a list of UPS accounts available to you on EasyPost.

Select one of the UPS accounts and give that account a nickname, then click "Save" to add the account to SKULabs.

(Optional) Once UPS has been added to your SKULabs account, you can customize which stores have access to it on the Carrier Accounts settings page.