Use an archiver like 7-Zip or WinRAR to extract the contents.
Most Rise of Eros mods are loaded via HWMI . You typically need to copy the dependency folders into the main directory of the mod loader (often where 3DMigoto Loader.exe is located).
Common components found in such dependency .rar files often include:
how to I put .rar files into my community folder? : r/MicrosoftFlightSim
This .rar likely only contains the dependencies . You may still need to download the primary mod loader (like HWMI from GameBanana ) separately if it isn't included.
Logic files that allow the game to recognize and toggle specific modifications. General Installation Instructions