Start with a nas, the rest will naturally come when you try to access your data for outside, or organize your data, or save more data types to your nas.

Your nas should be the central device and you build the rest around it.

Now, The question is, which nas? I would recommend synology, they are not too performance, a bit expensive and the company is lately doing suspicious moves, but the sw and the hw are rock solid and they are quite good for beginners from almost all angles. Extra point for how many howtos and tutorials are present in internet.

Once you are comfortable with them, you will realize the rest