How to Create an Additional Tree
Access your account by clicking your username in the upper right corner of the screen.
In the dialogue box that appears, click "Trees" to access a list of your existing trees. (You can also access this list by clicking on the name of your tree at the top of the menu on the left.)
At the bottom of the list, click "New Tree." This will take you back to the series of screens you went through when you first created your tree. Type in a name for your new tree and choose whether you would like to start an empty tree, import a GEDCOM file, or import people from FamilySearch.