Do you mean the fuel injectors or ignition coils?
The ignition coils are fairly easy. If you remove the engine cover you'll be able to see them. They're bolted down on some engines and not on others. They're quite easy to pull out and replace once any bolts have been removed.
The fuel injectors are a different story. You need to remove the inlet manifold to get to them and you'll almost certainly need an injector puller to get them out.
