In order to add a second channel or marketplace to RepricerExpress, click 'Channels' on your menu. On the 'Add New Channel' button choose the channel you wish to add to your account.
Once this process has been completed you need to enter your marketplace details. Find out more on how this process is done here.
Note: whenever you add a new channel with RepricerExpress it will always take 1-2hrs for your inventory to import.