3. What is ''partitioning'' a HDD? Do i have to, if i'm planning on using all the 1TB of my HDD for everything (booting os, games, pictures, music, etc)
Partitioning a drive will allow you to divide it into sections and assign each section a drive letter (D:, E:, etc.).
So you could create a 200MB partition, assign it a drive letter, and keep only pictures in it, for example.
Personally I would just create a new folder named C:\Pictures rather than creating a partition.