You can connect Easyship to SME99 directly from the SME99 dashboard.
To do so, enable 3rd Party Logistics (Easyship) in your shipping methods on SME99.
Once enabled, you will be asked for a Access Token or Key.
To find this Token on Easyship, go to your Easyship dashboard and the 'Connect' module.
Its located here: https://app.easyship.com/connect
At the bottom of this page you can find API, please press it.
Once done, you get to enter the name of your store and continue by pressing connect.
Once you have connected, your Store name should be visible on the left hand side under Connect.
On the Production part under this setting, you can press "More" and find your Access Token.
Please copy it and enter on SME99.