In the initial stage, you have to identify the data that will be collected or used to answer research questions and/or to test your hypotheses. Planning of the research data management should be done by creating a  (DMP). 

Data Management Plan

A Data Management Plan (DMP) is a plan that outlines how data is managed from the point of collection at the start of a research undertaking, all the way through to its analysis and elaboration of results and how it will be used beyond the original research undertaking. Typically, a DMP will cover areas such as data types, formats and volumes of data collected, metadata, quality control, scientific integrity, specifics concerning access and information concerning publications (as may be applicable). Platforms for the creation of DMPs.