Assuming you have aheadset and you do not need to replace it, steps are:
1) remove old forks after loosening all stem/cap bolts, be careful not to lose bits or lose track of sequence the headset parts have to go back on
2) remove old crown race from old forks
3) install old crown race onto new forks
4) either a) cut new forks steerer tube to same length as old, or b) if you want/need to experiment with stem positioned higher you will need to have more 1 1/8" spacers to install new forks with longer steerer or without cutting steerer
5) install forks/headset, depending on forks spec mustn't have more than 3~5cm of spacers below stem, but can have more above, spacers+stem stack must end up 3mm or so above top of steerer tube
6) install expander bung for carbon steerer into steerer (don't know if one comes with forks, if not have to buy one) and compressing the headset just so by tightening the cap bolt, then tighten the rest of the stem bolts.
For the above steps, 2) and 3) could use a bit of finesse and force depending on the type of race.
This might help give you some idea too. Further details on each step should be available somewhere from Park, Sheldon or Bicycletutor etc.
If you want to replace the headset, you will have to remove old headset from head tube, the degree of difficulty/tool requirement of removal and installation is dependent on the headset type.
Replacing forks is one of the trickier things to do on a bike. Given the forks including steerer is carbon here and superficial damage of carbon can significantly weaken it, if you are not confident you should get a good LBS to do it.