I guess you mean this?
which is a short extract from this
UKSALTWATERFLIES.COM: 50 Years Behind the Vise DVD
which is packed with good info for the first time swff tyer.
A decent hook, straight out of the packet, should not need sharpening but some will after a session. If its a good looking fly, which doesn't foul during casting, it'll be worth preserving for a while.
If the point dulls on one of mine, I use a simple finger nail file from Boots. The black emery board ones with a fine/coarse finish on each side. They're cheap and cheerful but very effective.
Try to get the point sharp enough to dig into your thumbnail as its dragged across.