Before doing anything, safety first!
Disconnect the coil wire first just to be safe.
Take off the valve cover.
Method 1
Using a 21mm socket wrench, rotate the engine clockwise looking at each cam lobe.
Point a the cam lobe straight down, and adjust a tappet, do this for each one until you are done.
Set to .008 with the engine warm/hot
or
Set to .010 with the engine cold
Method 2
Using same socket wrench, turn motor clockwise and set to top dead center with piston 1 on compression stroke.
You can check if it is at the compression stroke by taking the distributor cap off and seeing if its on number 1.
Rotate until cam sprocket is on NO 1.
Now check
INTAKE 1 and 2
EXHAUST 1 and 3
Set to .008 with the engine warm/hot
or
Set to .010 with the engine cold
Rotate the crankshaft 360 degrees so piston 4 (or your cam timing gear is on NO 4), is on the compression, you can check same as the first time with the distributor.
Rotate until cam sprocket is on NO 4.
Now check
INTAKE 3 and 4
EXHAUST 2 and 4
Set to .008 with the engine warm/hot
or
Set to .010 with the engine cold
Put valve cover on.
Reconnect your coil wire.
Check it again at 15,000 miles
Here is a video explanation.