Scroll down on the TreePlotter home screen until you see the numbers 1-4. Click on number 1.
There are two options when creating an account. You can use your Google account to sign in. (Just click the Google button)
Or you can create an account by typing in your email address and creating a username. You do not need a password. Choose a username that is easy for you to remember but does not identify you to others. Confirm that you are not a robot too.
Now you can add trees!