: Ensure you have a file named steam_appid.txt in your game's root directory (next to the executable). This file should contain only your App ID number.
Once InitiateDownload succeeds, you haven't downloaded anything yet—you've just opened the door. The next steps are:
: Accessing friend lists, achievements, and statistics.
: The Steam client must be running and logged into an account that owns the App ID (or has developer permissions) for initialization to succeed.