You can play ES custom maps in both single-player games or multiplayer.
ES@Canals_V2. rms ES@Metropolis_V2. rms ES@Capricious_V2. rms ES@Dingos_V2. rms ES@Shipwreck_V2. rms ES@Graveyards_V2. rms ES@Moats_V2. rms ES@Paradise_Island_V2. rms ES@Pilgrims_v2. rms ES@Prairie_V2. rms ES@Seasons_V2. rms ES@The_Unknown_V2. rms ES@Sherwood_Forest_V2. rms ES@Sherwood_Heroes_V2. rms ES@Team_Glaciers_V2. rms
Also, if your friends have custom maps that you would like to use, ask for a copy of the . rms files from them.
To access the “Random” folder on a Mac, open the Applications folder from your Dock and then open the AoE2HD folder. All resource files for the game, including the “Random” folder, are stored therein.