If you upgraded to a Growth plan, you will be able to create new list (the total amount of lists you can create is linked to the plan chosen).
To create a new list, you need to click in the Contact section. Then, click on the cog wheel at the right of the page.
Then, if you click on the first drop down menu following the 'Choose a list to show the appropriate attributes', you will see the last choice being: New list.
Click on it and then, you will be able to create your new list!