How to use electron-devtools-installer?

What I have

When it comes to installation and configuration the official documentation states the following:

All you have to do now is

import installExtension, { REACT_DEVELOPER_TOOLS } from 'electron-devtools-installer';

installExtension(REACT_DEVELOPER_TOOLS)
.then((name) => console.log(`Added Extension:  ${name}`))
.catch((err) => console.log('An error occurred: ', err));

That is a bit concise.

Questions

• Where should I place this code?
• How should I initialize it?
• How can I add multiple extensions?