Then I would stick to an off-the-shelf NAS. Start with the basics and then move to connecting it to the internet (some NASs have apps that will help you set this up). One other alternative is to set up a computer and install something like syncthing on both the computer and your laptop. So far impressed, but I haven't put it through its paces yet.

Regardless, you should be able to find tutorials on Youtube for most of these to help guide you through.