1) In your SureDone Account, go to Channels>Add Channel (https://app.suredone.com/channels/add)
2) Click on "Add Channel" option for eBay to add a new eBay instance.
3) The new eBay instance will be created as shown below.
4) Simply login to your eBay account when prompted.
5) When prompted, click I Agree to authorize the connection between SureDone and eBay.
You will now have a new eBay instance listed under Channels.