firing order and instructions for replacing cylinder heads

CYLINDER HEAD
Removal
Remove timing chain. See TIMING CHAIN . Remove rear timing chain cover bolts in sequence. See Fig. 10 . Remove rear timing chain cover. Remove camshafts. See CAMSHAFT . Loosen cylinder head bolts in reverse of tightening sequence, using 2-3 steps. See Fig. 11 . Remove cylinder head.
Inspection
Inspect cylinder head warpage at cylinder block area. Replace or resurface cylinder head if warpage exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. Ensure cylinder head height is within specification after machining.

thank you for the firing order. is it possible to get more detailed information on replacing the cylinder heads, please. the info given is too vague.

You need a repair/service manual there's procedures that you have to follow its not simple

This job is not for the normal DIY mechanic as you need to remove the oil sump and many other components. Repair details are too large to be printed here and a reair manual is the best option.