Each instance of MSP Challenge is created by loading a configuration file into the MSP Challenge server. This configuration file is a text file in the JSON format. A separate software tool for editing these configuration files is being developed. Either way, the configuration files stipulate almost everything, e.g. the time frame of the simulation, all the data sources that should be available, which simulations should be running in the background, etc. etc. This means that without a configuration file, there is no MSP Challenge edition or session.
When a configuration file is loaded into the MSP Challenge server, the server pulls all the requests data from the stipulated GeoServer, sets up the MySQL database for the requested edition and all its data, sets up the requested background simulations (e.g. Ecosystem simulation (MEL & EwE), Shipping simulation (SEL), Energy simulation (CEL)), and sets up any other more technical things required to get the MSP Challenge edition up and running.
See the North Sea basic, Baltic Sea basic, Clyde marine region basic pages for more information on what the default configuration files for these editions look like. If you've downloaded the entire MSP Challenge simulation platform, feel free to open up one of these configuration files in a text editor of your choice (all .json files in the 'config' directory of the server software are such configuration files) to see what they look like.