Removing an 088?! Ohhhh boy
I don't think there are any step by step instructions but if it weren't for the slip couple the system would be fairly easy to remove.
Once the air filter housing is out of the way:
1. Remove the turbo oil feed line from the top of the turbocharger and move it out of the way.
2. unscrew the intake hat (one bolt)
3. unscrew the two bolts where the turbo attaches to the pedestal
4. Remove pyrometer probe.
(I'm not sure if it is nessacery but I like to remove the two bolts where the pedestal bolts to the intake manifold to help everything "loosen" up)
Now if you slip coupler isn't seized up you can wiggle the assembly around to free the turbo and pull it out. Be careful not to force anything as you could damage the studs on the bottom of the turbo.
Once removed you can:
5. Remove pedestal.
6. unbolt downpipe and remove.
7. unbolt the exhaust crosspipe and remove.
8. Remove y-coupler (passenger side up pipe).
That said there is a good chance your slip couple is seized up. Last two times I removed an 088 I had to unbolt the front of the cab and lift it so the whole thing could squeeze out with the up pipe still attached. It is not fun and you will need a good vocabulary that includes many F-bombs
Hope this helps,
Andrew