Having done mine twice and done my dads now, it can be a real pain but the rewards are worth it.
How I did mine was unbolt the cat from the underneath at the down pipe end 4x 13mm bolts from memory.
Remove the rear breather pipe oil separator if you have one or just remove the rubber breather pipe, usually held on with spring clips.
Working from the top remove the bracket which hold the heat shield in place.
Remove the heatshield 3x bolts or screws
Remove the rubber breather pipe which comes from the metal rail.
Remove the metal rail held by 2 bolts hex type, allen key type from memory. Removing this rail can be fiddly as it goes around the rear breather pipe.
Then its a case of removing the studs/nuts for the manifold itself. Once the studs/nuts are off/out the manifold should just pull off the block.
Always use a genuine gasket and new studs/nuts from Vx as copies dont last as I found out.
The first time I did this I did it in a day, I can now do it in even less time with all the practice so worth having a go yourself.
I also recommend using some penetrating fluid on the downpipe to manifold bolts the night before as the y can break which is one downside. also if you can do the same with the manifold studs/nuts as this makes life easier when removing and hopefully helps to prevent studs snapping.
Good luck if you have ago yourself.