Nations without equivalents gain randomly generated ideas (though at the moment there appears to be a glitch where generic national ideas appear on the launch screen, as it seems ideas are only generated upon first launch of a game using the generated mod. Flags are carried over for the nations as well for CK2 nations that have no equivalent in EU4.
A CK2 save (from any year) is turned into a mod for the EU4 start-date of 1444, allowing the player to continue on to 1821.
