Chrome Desktop:
Menu -> Settings -> Search engine -> Manage search engines and site search -> Site Search (click “add” button)
Then fill out the popup dialog and click its “add” button:
Search engine: Ethereal
Shortcut: @ethereal
URL with %s in place of query: https://etherealsearch.com/?q=%s
Below the “Site Search” heading click the three dots at the “Ethereal” row and click “Make default”.
Chrome Android:
First search for something with this search engine in the Android Chrome browser. Then:
Menu -> Settings -> Search engine -> Select: etherealsearch.com