Homicide INvestigations

Where: small rural town outside Baton Rouge, Louisiana 
When: Present day

I tried googling "murder investigation procedures" and "Criminial investigation procedures." I'm getting such a vast amount of information, I need someone who knows the basic gist of what steps of a murder investigation are. What are the basic chain of events?

A body is discovered. Nude, with no id or evidence found at the scene, we have a Jane Doe. The autopsy is completed - we have a COD. The detective is already searching missing persons files reported in the recent weeks. Now what? Can someone provide a basic timeline of events it takes to conduct a murder investigation? How long certain tasks take. I've seen "ask a cop" mentioned here, but I have no idea what that is or where it is. I suppose I could google it. 

Any and all help would be incredibly helpful. Also, this will be a serial killer thing - so once there is another body found, obviously linked to the first body, how does that change things?