Assuming you've npm installed, you'll need to do a few more things in order to get a running copy of this project up. You'll also need PostgreSQL and redis and you'll need to setup a secrets.json in the root of the project with appropriate ports and secrets (this will probably be changing soon).
You should be able to start redis with npm run redis. Assuming you have the redis server running (look for a process redis-server) and a running PostgreSQL installation, you can run npm run update-schema to update the GraphQL cache of types, and then npm start to actually start the server.