In order to edit your contact list settings, you need to navigate to the list you wish to edit by clicking the menu "Lists" in the left side menu.
Then choose the list for editing. If you have many list´s you can use the search field in the top right corner. Click the "Open" icon which you find here:
You will now see a new "sub menu", where you click "Settings".
Here you can edit your contact list settings. Remember that these settings affect the content that´s automatically added to your e-mail campaigns, such as the from details in the bottom.
Remember to save your changes in the top right corner.