Missing package folder after run Custom build

[notrealdev]

Hi, I am trying to create a custom build for my website, follow the document here.
When I run npm run build:prod, nothing happens, the package folder is not created.

Check my image:

Did I make a mistake or mistake somewhere?
Can anyone help me to solve the problem?

Thank!

[nolimits4web]

It is in the dist folder

[notrealdev]

I have seen, it is ignored in the file .gitignore
Should you also update the document?
Thanks!