Read a book on it just like LATS said... there's so much info about it... Plus there are different ways to go about installing frets besides hammering. They make presses and they make slides now as well. The press is exactly what it sounds like... a press that presses the fret into the slot... and a slide is the same way... you slide the fret in rather than hammering or pressing... I personally have only used a press...
Second question:
To the one about whether a refret should be done or you should buy a whole new neck.... If you have a Gibson... I would suggest a refret. When you have to deal with set neck guitars, changing necks is never usually a great idea... If it's not done right... for some reason... It could come lose and so forth... I would suggest a refret... Which may be the more expensive route... but it's a lot safer. I guess it also depends on if you like your neck profile... if you really like your neck profile then definitely keep the neck and go for the fret job. If not... I guess consider the neck swap... But make sure that you're taking it to a certified luthier... or someone with TONS of experience.