In unity Editor, How to make all cs files into Dll ?

Version 2018.4 I want to makes all cs files into a dll(or some dll). Others just need the dll and can run Unity well. They can add components as usual. The only difference is they cant read code files. i try to use assembly definition, but some namespace or type error comes('NUnit', 'TMPro','ColorMode'). i dont know how to fix it . then i try another way. Copy files and dlls and compile the four projects(Assembly-CSharp-firstpass, Assembly-CSharp-Editor-firstpass, Assembly-CSharp, Assembly-CSharp-Editor) step by step . But when i try compile Assembly-CSharp-Editor, i fail. error: Error CS0433 The type 'BuglyUtils' exists in both xxxxx