The plebe regiment will be herded en masse into Dahlgren Hall the first few days of Plebe Summer to take English I and II, Calc I and II, and Chemistry I and II validation tests. Everyone goes together; those who have validated through AP will not be separated from the group.
Those who do well on the initial validation tests for Chemistry and Calc will be invited later on to take Physics I and II and Calc III. Because AP scores will not be delivered until later in the summer, if you want to validate Calc III and Physics you must do well on the Calc I and II and Chem I and II tests administered by USNA.
Language validation tests are administered a couple of weeks later, toward the end of first set. They are electronic multiple choice tests. The scores are processed and interpreted by the department. Despite what the internet says, it is possible to validate more than two years of a language; it is common for heritage speakers.
Long story short: You will be taking the exams for English, Math, and Chemistry. You won't have a choice.
That's how it worked last summer.