How to create a sidebar? Where can you read about it?

Question

Google Apps Script

Hello. Where can I read about how to create a sidebar in a google spreadsheet. I ask everyone who can help to respond.

Answer 1

A sidebar is a normal HTML page. One example was enough for me for my tasks, then everything became clear.
(googled for " [Examples, Google Apps Script] Developing Google Spreadsheets/Scripts Add-ons ")
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HtmlService.createHtmlOutputFromFile
GoogleScript Sidebar

Well, nobody canceled the official certificate and guides , they are pretty good.