**Study Overview:** This study is testing a medication called *Cenobamate* for adults with a certain type of epilepsy known as *partial-onset seizures* (POS). Cenobamate is already used in the US and other countries, but this study wants to see how it works when used alone (monotherapy) in adults who are newly diagnosed with POS or have had it come back. **Key Points to Consider:** - **Length of Study:** The study lasts about 1 year, including different phases like treatment and follow-up periods. - **Visits Needed:** Participants may need to visit the study site multiple times over the study period to monitor health and seizure activity. - **Treatment and Risks:** The study involves starting with low doses of the drug and gradually increasing. Participants may face risks like side effects or seizures. Participants must be between 18-74 years, have had POS before, and meet certain health criteria. They shouldn't have specific conditions or recent drug use that might interfere with the study. Women who can have children must use birth control. Participants and/or their caregivers need to track seizures and report any side effects.