Download your product zip file, extract the product folder, and locate the folder containing the preset files. For "Ambient Echoes for Valhalla Super Massive", the preset folder is titled "TWS - Worship Spaces".
Open the following location on your computer in a second window, please note the location will vary depending on your operating system.
macOS: Macintosh HD > Library > Application Support > Valhalla DSP, LLC > Valhalla Super Massive > Presets > User