As Dave suggests this is not a desperate job , but you will need to work very methodically and it will take some time.
I would first remove the bonnets entirely to give you good access, and lay plenty of protection over the wings.
Then start taking photos , lots of them, to show you what it should look like.
Then ensure that you have a clean surface to accept all the parts as they are removed.
Now label everything very carefully as you remove it , and ensure that you mark the correct orientation.
Once everything is removed you will probably have a lot of cleaning to do because if the gasket has deteriorated then the chances are there will be some corrosion on the heads, and there will also be a lot of old sealant around the edges of the gasket. If you want to avoid getting any of the dirt etc into the engine it is important to protect the camshaft/lifters area with a good mask, and the same for the intake ports in the head.
This official Land Rover video goes through a lot of the EFI engine and its parts and may be worth a look if you are unfamiliar with some of these BUT what it lacks in brevity it more than compensates with length , so be warned.
https://www.youtube.com/watch?v=yLYwG_QSW4wGood luck
