Go to the skills map and search for the skill you would like to test using TalentScore. If the exam is configured with this skill you will see the 'Test' option in your skill scores. Click on 'Test' button to invite yourself to the exam.
Go to your profile and click on the 'Evaluate skills' button in the Skills overview section. Then, select the skills that you would like to evaluate using TalentScore and confirm by clicking on the 'Evaluate my skills' button.