Integrating ChannelSale with ShipStation is a fairly straightforward process. It will require only your user login credentials and your order statuses from ChannelSale. Make sure you have the correct statuses, and go to ShipStation.
Head to your Account Settings (the wrench icon in the upper right).
Next, select Selling Channels and then Store Setup from the sidebar on the left.
On the page that appears, click +Connect a Store or Marketplace.
Select ChannelSale from the list of stores.
On the popup, enter your username and password and input the statuses.
Once you enter your info, and click Connect.