No "how to guide" but its a challenging job, if you dont have a ramp
Get the car at a decent height then mate and you might want a friend close by.
Turbo heat shield
Lambda sensors or just unplug both of them.
Undo 3 bolts at turbo (usually stupidly tight)
Remove 8mm bolt holding cat to manifold ( very hard to see so might have to feel around)
remove drivers front wheel
REMOVE HUB NUT
Split track rod end from hub.
Undo the 3x13mm bolts holding wishbone to hub.
Remove vertical drop link
Remove engine under tray
Remove subframe crossmember
Undo driveshaft clamp
Remove lower dog bone engine mount and all brackets attached to engine
Undo some 8mm bolts holding cat to engine, etc
Undo nuts holding cat to exhaust flexi part
Undo exhaust clamp and remove front pipe
Then it should be a lot of wiggling of the cat and a mate rocking the engine to give a bit more space.
Man I was a bit surprised when my local specialist wanted £50 for a cat back but £200 with a decat. Now I'm starting to learn that it's actually a pretty good price for the whole lot. Why is everything on Renaults such a pain in the arse? lol