Pre-launch activities include:

Pre-Project Planning: Mars 2020 has completed its concept and requirements definition (Phase A) and its preliminary design and technology development (Phase B).
Science Definition and Instrument Selection:NASA selected a team of scientists to propose mission objectives and desired capabilities. Scientists proposed instruments capable of meeting mission objectives.
Final Design and Fabrication at NASA's Jet Propulsion Laboratory: The Mars 2020 mission team is building parts of the rover and its spacecraft (Phase C).
Landing site selection:The Mars 2020 team considered 8 potential landing sites. The final selection was 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 will make a journey from its California birthplace to Florida in preparation for launch.
Assembly and Testing at NASA's Kennedy Space Center:Once the Mars 2020 spacecraft arrives at Kennedy Space Center in Cape Canaveral, Fla., the mission team will still have considerable work to prepare the spacecraft for final assembly and launch.