the below should cover most your questions, but i think that most of it's covered in a tutorial. only way i can explain i understand as well as i do


1)
select the ships, bottom right, second from right icon opens fleet options (hotkey 'f') then click the create fleet icon (hotkey 'f' again)


2)

a) fleets can be pinned, so they're always in your empire map

you can tell a fleet how spaced out you want it (tight, normal, loose) and the area you wish to attack (Gravity well, local area, hold position). also when phase jumping you can tell the fleet to only jump when everyone's ready (right click the move icon when the fleet is selected, so you can arrive in one big mass, rather than piecemeal.


3) no


4) same as 1) but you can also use the disband option (hotkey 'd') to remove selected ships


5) select fleet, open fleet options (hotkey 'f') and disband (hotkey 'd'


6) still a noob here so not from me, though personally i find this system a bit cumbersome compared to ctrl+#, though it adds the useful features listed in 2)a)+

I will add to mrlarone's list:

-Fleets have their own special AI. Support ships will go behind in the formation, attack ships in the front, etc etc, they can attack something if you give the order and they will come back to the fleet formation after the target is destroyed, and a few more little details.