In order to initiate a civil lawsuit in a federal court or in a state court, what should the first thing that you should do?

In order to initiate a civil lawsuit in a federal court or in a state court, you should prepare the complaint which describe your damage or injury; your request to compensate for the damages/

Explanation:

The process of a civil lawsuit is guided on website of United State Courts; in section of Civil case.

A federal civil case involves a legal dispute between two or more parties. In this case, it's your dispute so you have to prepare a complaint / report for what we are asking from defendant for what they made you affected illegally. So that the court have reason to initiate a civil lawsuit.