From where to start

[Men]

Hi coders,
I have a question, i started developing a new RAT, but i would like some tips.
From where is better to start?
I started by the C2 infraestructure (server, DB, etc) before coding the malware, or should I code the malware before C2?
I have ever coded some scripts to some orgs, but not like this, from the point zero.