A copy of the manual (downloadable from here) will tell you most of what you need to know, it has sections on engine removal and transmission disassembly & reassembly.
Based on your updates since and that it's a 2014, there is indeed also a strong probability of circlip dislocation and subsequent associated damage.
Even if the actuator bolt isn't the problem this time, it needs to be addressed while in there. Have seen it cause a shifter jam too besides the floppiness symptom which is most common.
As above best open it up and find out what the issue is first. But in any case you'll need a couple gaskets (RTV silicone from local auto parts shop will do all but the sump gasket may be best get the Triumph paper gasket) and a set of crankcase bolts. You can reuse the main bearing bolts. Will need a rotor brace and flywheel removal bolt, can give you dims if you're alright making them yourself. A clutch brace would make life easier though not essential.
And the manual is wrong where it says you need the sliding hammer tool & coupler to remove input shaft, you just use 3rd/4th input gear as the sliding hammer.
Also there's a few little upgrades can be done while in there if you're interested.
Can you make a video clip showing the noise etc?