820.1. Repeat is an Optional Additional Cost keyword.

820.2. When a spell's effect is performed an additional time with Repeat, choices must be made at the usual time during the Make Relevant Choices step of Playing a Card. See rule 349. Playing Cards for more information.

820.3. Multiple instances of Repeat can be paid for separately. The spell's instructions will be executed an additional time for each instance of Repeat that is paid for.