Try swinging a 3' axe in a room, given 2 foot arms. You would need at least 5' right, left, fore and aft. A room 10' square would give you a 10 foot "swing".
Put a china cabinet in the room and you have a reduced swing "over the cabinet".
Remove the chuck and replace it with a dead center such as you find on wood lathes and were once "standard" on metal lathes then slide the tail stock away from the head to the max and you have so many inches "between the centers".
Try searching those terms on Yahoo or Google.
ALL of us were green horns at some time so don't be bashful about asking, but a bit of advice: try to take a "machine shop" course in some community college. Machines can and will KILL YOU just for just stupid mistake and you won't know what is stupid till you are educated. Best not get that education in the "school of hard knocks"!!!
(For example, don't touch a turning piece in the lathe with a piece of fabric or a gloved hand
Good luck, hang in there and READ!