Before You download the Calendar, You have to decide which database You will be using.
The M version runs on a MySql database. Your ISP must provide this service.
The L version runs on a MySql database. ( The database is "included/built in" in the L version )
If You expect wery heavy traffic and a huge amount of data, I would suggest the MySql. But for the calendar, this is not an issue.
Even for the more experienced use of the calendar, the amount of data, and the trafffic, should not be a reason to choose the one database over the other.
A reason could be, that You have a tool/program You want to use in connection with the calendar database, and this tool only runs on one of the databases - then You should use this database.
If You are not familiar with any of the two database types, I would recommend the SQLite base, as it is the easiest to use under installation.
A quote from the LuxCal Forum. The post is put in by the author of LuxCal, Roel Buining.
Some users think that the SQLite database is for Windows servers only. Wrong, it's not! LuxCal - SQLite is a mature alternative for LuxCal - MySQL, on ANY SERVER running PHP 5.3 or greater.
So why would you prefer LuxCal - MySQL over LuxCal - SQLite? I don't know!
The SQLite database is held in a separate single file at a location of your choice. No set up or administration is needed, just tell the calendar where to store it and what name it should be given and that's all there is.
When running multiple calendars, each individual calendar will have its own database file, which name corresponds to the calendar ID. So handling the individual databases is really easy; just a matter of copying, moving, renaming, or whatever you want.
The MySQL database is running on a (maybe virtual) database server installed by your ISP. Before installing the calendar, you will have to create the database, using tools provided by your ISP. The database is defined by host (db server) name, user name, password and db name.
When running multiple calendars, each individual calendar has its own set of database tables in the same MySQL database. For each calendar, the relevant set of tables has a unique name (the calendar ID) prefixed to each database table name. Handling the individual databases can only be done via software tools.
So, again, why would you prefer LuxCal - MySQL over LuxCal - SQLite? You probably don't.