“Then sleep in before lunch.”
Sleep in means to intentionally sleep later than usual, often on a day off. Oversleep means sleeping too long unintentionally, for example and becoming late.
A2-57 / CEFR A2 / EPISODE 57
Making plans after exams
SceneTina has finished the term's last exam. A two-week break is approaching.

WORDS & CONTEXT
Sleep in means to intentionally sleep later than usual, often on a day off. Oversleep means sleeping too long unintentionally, for example and becoming late.
"Even more rest!" On top of sleeping in, Tina conveniently decides that sitting down at lunch counts as rest too.
A draft is a rough version of a piece of writing, so this means "I made three drafts." It is not about how many times he rewrote it; it says there are three drafts. Frank had prepared the plan the day before and is now adding the lunch he has just heard about. The punchline is his thoroughness: he made three drafts of a simple plan — sleep late, have lunch with friends, enjoy the break.