Pre-launch activities include:

Pre-Project Planning: Mars 2020 completes its concept and requirements definition (Phase A) and its preliminary design and technology development (Phase B).
Science Definition and Instrument Selection:NASA selects a team of scientists to propose mission objectives and desired capabilities. Scientists propose instruments capable of meeting mission objectives.
Final Design and Fabrication at NASA's Jet Propulsion Laboratory: The Mars 2020 mission team builds parts of the rover and its spacecraft (Phase C).
Landing Site Selection:The Mars 2020 team considers more than 60 potential landing sites. The final selection: Jezero Crater.
Assembly and Testing at NASA's Jet Propulsion Laboratory:Engineers assemble and test the Mars 2020 rover in a clean room at NASA's Jet Propulsion Laboratory (Phase D).
Shipping the Spacecraft to Cape Canaveral:The Mars 2020 rover makes its journey from its California birthplace to Florida in preparation for launch.
Assembly and Testing at NASA's Kennedy Space Center:Upon the arrival of the flight hardware at Kennedy Space Center in Cape Canaveral, Florida, the mission team completes considerable work to prepare the rover and spacecraft for final integration and launch.