i'm really noob about Mac

[acuariano]

hi guys
i always work in windows..my uncle has a mac machine..i don't even know if is a i06..and i have some questions about it..
the machine is in te box...
-what would be the first steps to take?
do i need to be connected online to fill his information
-does it come with a reinstallation disk in case i have to reinstall the system
-do i need an antivirus for it?..and which one?
can i make an image backup on a disk or partition ,do i need a third party software to do it] in case the system becames unbootable
do i need protection to surf the web..do i need a program like sandboxie

i have more questions..and thanks in advance for your responces