Version A) different seasons worldwide:
Create new folders Spring, Summer, Autumn and Winter or similar.
Place them wherever you want them to be.
Make sure, each of them has an own SCENERY and TEXTURE folder.
Now you need to search for the file worldlc.bgl -this one calls the textures.
Put a copy in each SCENERY folder and the suiting ground textures in the TEXTURE folder.
Now start your game and add each folder like normal scenery via the menu.
Make sure to put them in the hierarchy near the place, where the normal worldlc.bgl is called.
Now you can enable your seasons just by a click. Enabling more than one only has the result to see the first files found by the game.
I use this way of organizing my seasons for years.
Version B) Europe
If you have downloaded Sander's Landclass cfs2_EURW_LC.bgl (which is just an enhanced European part of the WorldLC.bgl) - you can do the same, when putting this BGL in your season's scenery folder.
See example. At the moment I am using European summer textures, which are placed with Sander's LC.
On top are the other files like Mesh, Shorelines etc.
Some of these scenery files are actually doing the same. So I put a prefix 01-04 in the entry of the list just to inform myself.
I need to enable one of each to have the set complete.
(01: Winter OR Summer OR Spring)
Hope I could explain good enough.