There are 2 ways of decompling thing in dnSpy
1. Edit class
2. Edit method
Edit class will decompile the whole "class", which likely give you like 1000+ lines of code which is not only hard but also prone to error.
From the spoiler, you can see that this whole class contain like 800 lines of code which contain a lot of thing.
If you try to edit class, you are likely to rum into error when you try to compile, so use the edit method instead.
Edit method will not only give you fewer lines of code but the complicating things from edit class are also not exist in there, so it is less likely to cause error when you compile granted that you did not write anything wrong in there to create an error.
eg. If you want to edit the KMod's dialogue, go to GameManager/OnGUI
Tip from me (because it happen on me)
When using if-else argument, after compile make sure that it did not turn if-return. How to fix this? TBH, I do not know myself, sometimes it happen, sometimes it not.
Good luck on your modding