very easy if you're mechanically inclined.
Pull off the valve covers
Yank off the rocker arms.
Get an air chuck and thread it into the spark plug hole and hook it up to your air compressor. This will stop the valve from falling into the cylinder when you take the spring off.
Using a good spring compressor, compress the valve spring and use a magnet to pick up the valve locks. Remove the valve spring.
Just pull the old seals off and throw them as far into the woods as you can.
Press on the new seals ( Hopefully you sprung the extra $$ for the good Viton* seals) using a socket and a rubber mallet to tap them onto the valve guides.
Replace the spring and keepers.
Move onto the next cylinder and repeat 7 times (or is it 14?
Replace the rocker arms. DON"T FORGET TO ADJUST THE ROCKERS!!!!!
Replace the valve covers and you're ready to roll!