Various tools have been designed to help with data extraction. See links below for the one that best suits your needs. For further clarification check with your supervisor or tutor.
Data Extraction - pulling out the information from individual studies
The following tools can be used for Data Extraction
Data Collection Form - you must answer as many of the questions in the Data Collection form as you can. The Cochrane Library has an example of a Data Extraction and Assessment Form template that can be edited to suit your requirements.
Data extraction will pull out information from each of the studies on, for example study type, number of participants, population, setting etc.
If you are unsure about what data should be extracted you will need to have these conversations with your tutor or supervisor the Library is not able to advise on these types of decisions.