You can (and should) choose one of those sites with the least traffic bottleneck (you might try, and see how fast your downlaod goes).
Where the files are hosted ( the files are identical across all sites, you only need to download one of them). You can click on the desired tile in the following, dynamic map, which will open a little balloon, including the file name / file size and the direct link to one of the mirrors: PLEASE READ AND FOLLOW THE INSTALLATION INSTRUCTIONS CAREFULLY, as most of the problems result from an incorrect installation!.But by lowering rendering settings, you might get away with less VRAM too. 4-6 GBytes of VRAM (on you graphics card) are recommended, esepcially if you use other add-ons too.16 GBytes of RAM are highly recommended (32 GBytes are optimal)! Although some areas might work with 8 GBytes of RAM too.Your X-Plane 11 FPS might become very low (if you already have FPS problems, this will not improve your situation!).Single file sizes go up to multiple GBytes! In the map you can see the size of each tile. You might need a very long time to download all tiles.
HD Mesh Scenery v4 can be seen as a vastly improved version of the default scenery shipping with XP11.
IMPORTANT: Coverage to the north ends at 73 N !! Hawaii and most of the tiny Pacific Islands.Europe (from the Canaries and Iceland in the west up to Moscow an and most parts of Israel in the East).