Using Cloud with Xbox and as Pc

Hi! New dad here who finally has more time to use this beautiful device!

I have two questions, first is how can I use it as Xbox remote? Do I need to own Xbox or I can use it if I can create account? I had PS and I need to have it on and then stream it to Cloud, which is not always practical

And second one is that I want to use it as PC or to use maximum of it, what is your experience with that?