First step, you will need to navigate to the "Integrations" tab at the top of Listing Mirror and select "Channel Integrations" from the dropdown.
You will be taken to your Channel Integration Page where you will select the icon of the marketplace that you would like to add into Listing Mirror under "Add New Channel Integration" (#1). Then, select which marketplace you will add by clicking on the round logo button (#2).
Each integration will differ with steps that you will need to take. Follow these instructions, letting us know if you run into any difficulties along the way.