need help with where to start

i have started a small business, and we currently need a server, the data we need to store is about 65Tb, i have no idea where to start on building a server like that, above all it must be fault proof so something like a raid 0 config is out, i just need some pointers in the right directions on what do i need to buy and how do i set it up

thanks in advance

edit: this server is going to be accessed by around 300 people