You should receive an email like the one you see below, click on Set up account to get started.
Fill in your email address and last name to get started, then click Next.
Another email will go to your account that you need to click on to validate your account.
Click on Create Password
Set a password and then you will see a notification that setup is complete.
Click Log In.
Turnitin will then ask you for a security question to complete your account setup.
Accept the end-user agreement next.
You should then see a dashboard similar to what you see below.