Good evening, in fact I am performing an integration of demo2 HTML theme by following all the steps contained in the document Server-Side integration for laravel.
once you get to the step to compile the assets.
when I run the command: npm run dev
it shows me this error:

'mix' is not recognized as an internal or external command,
operable program or batch file.
npm ERR! code ELIFECYCLE
npm ERR! error 1
npm ERR! @dev: `npm run development`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the @dev script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\..\AppData\Roaming\npm-cache\_logs\2022-02-15T02_39_15_364Z-debug.log.
In the stage of Preparing Theme Assets
I see you noted this: Copy source folder from theme/src and paste it into laravel/resources. in my case I can't find the src folder in the theme but rather in theme/demo2/src.
so is that why I find the problem?