How do I mount an external ntfs formatted harddisk manually and through /etc/fstab?

[Jens Rasmus Liland]

Hi,

How do I mount an NTFS formatted external harddisk plugged into the computer
using a usb cable? And what do i write in the /etc/fstab after being able to
successfully mount it manually?

I have some blurry understanding after reading a bit in handbook that the
harddisk's NTFS partition is at /dev/da0s1 by default. I have installed
ntfs-3g from ports.

/Rasmus