How to get the Icon for custom elements?

Visit https://pictogrammers.com and look for an icon. Click on the symbol and on "< / >" in the upper line, this copies the complete symbol including HTML to the clipboard. Please paste this text into Notepad or another editor. Search for the text in d here, copy it again and then paste it into the line in the energy flow adapter. If you typed it correctly, it will replace the current question mark symbol.