Note: that this will contain only the terrain data, and no waypoints.
First of all, quit the server and wait a bit, so the map data files are written to your disk. Now open the map data cache directory:
Windows: go to %appdata%\.minecraft\mods\VoxelMods\voxelMap\cache
Mac: go to ~/Library/Application Support/minecraft/mods/VoxelMods/voxelMap/cache
Then create a .7z, .zip, or .rar archive containing the directory of the server (e.g. play.civuniverse.com), and submit it to my Google Form. If it's a lot of data, you might need to upload it to a file hosting service of your choice (for example PixelDrain or MediaFire) and send it to me via discord @MadDog443#4618.
^ Edited and taken from the CivMap Repo Wiki
Just watch this really simple video and dump your files into the Google Form or go drop them in the Offical Discord.