Repetition is the key weapon against forgetting

Everything you learn with SuperMemo will come back to you for review and repetition. Every day, you should review your scheduled portion of the learning material. Start with pressing Ctrl+L, or Enter, or choose Learn (if visible).

Use Enter to go from page to page. Sometimes, SuperMemo will ask you to grade yourself (e.g. Bright, Good, Pass, Fail, etc.). In such cases, click the grade that best reflects how well you remember

(optional reading at supermemo.com: General Principles of SuperMemo)