[Konewka]

According to your third question - you will need to learn some basic stuff about SQL. However, it may look difficult to understand but after all it comes out to be pretty easy. First of all you need to connect your SQL to your gamemode, then you can start thinking about how to insert data into tables. Remember that you will need Apache and MySQL server (such as XAMPP) for local actions. If you find it too hard you can still come back to some classic solutions, like saving data in .txt file.

Regards.