I need to put all my files in a central location on my home wi-fi network so that they can be accessed from family members. My requirements would be to set up :

a) a place where files such as pictures, videos, music, documents etc would be accessible to family members
b) a place where family members could back up their own files

I thought I could get a external hard drive and attach it to my router (via usb) and using some sw application to back up/syncronise data (e.g. FreeFileSync) . I understand this may not provide the fastest way of accessing files, but I need something simple to implement and manage.
I have read other topics from this forum but I am at a loss regarding NAS and RAID terminology, and frankly it all seems too much for my needs.

I understand that the perfect solution would involve redundancy but at the same time I do not have a lot of cash to spend on a 2 disk solution, so I am resigned to rely on the improbability that both the original system (e.g. daughter laptop) and the common hardware both fail at the same time.

Anyone willing to share some wisdom and advice on the best way to solve my problem?