Using mono.Cecil to inject code into compiled c# unity (assembly-CSharp.dll)?

[dan771]

So I have been devloping some mods for a game by decompiling and compiling using dnSpy (which only does for certain modules/classes as certain classes cannot be recompiled). I have original dll (A) and then i have modded dll (B) (some mods have been made by other ppl too besides me) and would like to make an installer that converts A into B because the devs are strict on sharing game files. I was told mono.Cecil can be used for this and have managed to get it working in VS but not sure where to start in making this . Also, if anyone has any other better ways of going about this be great too. Thanks!