Access wanted to Public share only from my mobile devices

Hi, new user here - very happy so far, but I am struggling to find the correct combination. I want to limit access to certain files on the cloud and my mobile devices.

I have created folders that I want to use on those devices in the Public folder and created folders I want to remain only accessible from my home network in another share.

I do not seem to get the right combination to do this - looking for some advice please

Thanks, Simon