Stricly speaking, a ‘database’ is a collection of information. The information stored on this web site could be considered a database. So could a bunch of tape files.
Today, when one hears ‘database’ one tends to think of ‘relational database management system’ and this cause some confusion because a ‘relational database management system’ (RDBMS) implies so much more than just a group of information.
Your questions are not simply to answer – the answers are quite involved.
One could create a database with very little understanding, I suppose. But in truth, one needs to understand many concepts.
Different products, different platforms, different needs, different business rules, different uses … all this means that some heavy duty analysis and learning is needed before you just jump in and ‘create a database.’
Happy New Year.