Make sure Rust is not running.
Download the Ancient loader using Loader Download.
Place the loader in a folder on your PC where you can easily find it.
Disable any antivirus software that could block the loader.
Launch the loader.
On first launch, the loader may download an update and close. If this happens, reopen it.
The loader may randomize its filename, so keep it in a dedicated folder.
Alternative source: Loader Downloads.
Synthera Docs