Following https://github.com/DataVisHub/gojs-course/blob/main/lessons/lesson-0-project-setup-and-intro.md
It is not explained that I need to download the files from https://github.com/DataVisHub/gojs-course/ and execute

npm run start

from the top level folder so that the package.json file is present.
Otherwise, the failure occurs:

c:\>npm run start
npm ERR! code ENOENT
npm ERR! syscall open
npm ERR! path C:\package.json
npm ERR! errno -4058
npm ERR! enoent ENOENT: no such file or directory, open 'C:\package.json'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

I'm trying to follow:
https://github.com/DataVisHub/gojs-course/blob/main/lessons/lesson-0-project-setup-and-intro.md
When trying to execute:

npm start run

I get the error shown below:

C:\rw_apps\dev-junk\gj1>npm start run
> family-tree-builder@1.0.0 start
> vite "run"
'vite' is not recognized as an internal or external command,
operable program or batch file.
C:\rw_apps\dev-junk\gj1>

I think I resolved the problem by running

npm install vite

Also the version of npm / node / vite /etc. are not documented.
I tried to use:

C:\rw_apps\dev-junk\gj1>npm -version
8.8.0
C:\rw_apps\dev-junk\gj1>node -v
v18.18.2

but when the VITE app is running, I get HTTP 404 errors

  VITE v6.3.5  ready in 403 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help

Firefox Developer Tools response documented is:

http://localhost:5173/ sent back an error.
Error code: 404 Not Found
{
	"responseHeaders": {
		"headers": [
			{
				"name": "Connection",
				"value": "keep-alive"
			},
			{
				"name": "Content-Length",
				"value": "0"
			},
			{
				"name": "Date",
				"value": "Tue, 27 May 2025 15:57:03 GMT"
			},
			{
				"name": "Keep-Alive",
				"value": "timeout=5"
			},
			{
				"name": "Vary",
				"value": "Origin"
			}
		]
	}
}