Note: The following guide is based on the tool I received from
SPX Motorcraft and which I was able to take apart easily.
 

If you have never used this tool, I strongly recommend that you
practice removing and replacing the cam followers on cylinder
#4 first. The reason for using #4, is, it's in the open and everything
is easy to see.
 
 

Note: I laid a piece of lint free cloth on the head surface, to help prevent
nicks or scratches from the tool.
 
 

Ok, here we go....
 
 
 
 

Take the base of the tool as shown here:

Slide it under the cam :

Now position "the foot",  as I call it:

Place the top "wheel" on the tool and start the threads just a little:

Now you will notice, that as you turn the top wheel clockwise, the
"foot" moves downward and starts compressing the spring.

The "foot" will need to be angled a certain way, in order for it
to have movement downward, without hitting parts of the head.

WARNING - IMPORTANT!

Make sure that as you compress the spring, the valve stem
is going along with it, if it's not, you should press down on
it with your finger, every so often. If you don't press often enough,
the valve retainer keys may come apart and fall off of the valve
stem. Avoid this, because not only will you need to reassemble it, one
or both retainer keys could fall into an oil galley way.

If you start compressing the spring and the retainer keys immediately
start separating, reposition the "foot" of the tool and try again.
 

The spring should compress nicely and you may or may not, need
to press the valve stem down (with your finger) as you go along. The
valve stem should press down fairly easily with your finger, if everything
is setup correctly.

Once the spring is compressed and the valve stem is down, then go
ahead and either remove or install the cam follower.

Now you will simply turn the top of the tool counter clock-wise, this
brings the "foot" back up and now you can disassemble the tool and
move on to the next valve spring.
 
 
 

The #1 and #8 cylinders are slightly more difficult to do, because of
limited visibility.
On cylinder # 1, I found that getting my head down where the
battery tray was and looking over to the right, allowed me to see
enough of the valve spring, to get the tool set up.

On cylinder # 8, you do pretty much the same thing, your head goes
down as low as possible and you look over to the right. When I was
practicing my cam follower procedures, I took a pic of how the
tool gets set up on #8, that way when it came to doing the real
cam swap, I knew how to set it up again.

It can get a little frustrating trying to get the tool setup.....just be patient and
keep trying.