I'm a totally newbe titch.io

I have just uploaded a game that I developed using react and typescript.

It works on my computer using npm, but I need to test it on a mobile or pad.

I have uploaded a zip-file as described.  But no game visible at https://arenol.itch.io/calmdow

I don't understand what I am doing wrong.

Your profile doesn't show any games. I think the problem is that you still have the page in private mode. I recommend reading this part of the Itch documentation on creating pages:

https://itch.io/docs/creators/getting-started#publishing

Your game page is trying to access files at the root of the domain, e.g. "/assets/index-B3pFYL4m.js". You can see error messages if you open the browser console while starting your game. You need to access files relative to your index page, without the first slash, e.g. "assets/index-B3pFYL4m.js".

Fixed it.  It's "npm run dist" that didn't make the relative paths correctly.