Hello ivan sunata !
If you don't already have Turnitin at your institution, you'll need to contact our Sales team, so they can get your school set up. Visit https://www.turnitin.com/contact.
If you already have an account and just need help setting up an instructor profile, you can visit our Help site (https://help.turnitin.com/Home.htm) and search for the answers you're looking for-- we have many helpful guides in setting up accounts and troubleshooting.
Any other questions, feel free to email our Customer Support team directly: firstname.lastname@example.org
Hope this helps!