Help and advice on building a media server

[NickMate]

Ok, I'm building a home theatre in a few months and decided to go the HTPC route since it's worked out for me so many times. I know how to build a pc and all the software to go with it but I'm very unclear on how to build a media server.
I've converted a Blu-ray to mkv (retaining it's video/audio quality) and on average each film is about 30-45gb each. So I have over 300 Blu-rays and that will only increase as time goes on so I've settled on either 16 or 20tb to start with. How would I go about doing this. What components will I need, the max I will spend on a server is $1200, that's Australian dollars as well
I basically need to to what components, how to install them properly and how to set it up as a server.
Any help is good, as long as it's helpful

Thanks guys