Once the literature is sourced, the process of reading, assessing and evaluating the literature within the search question and criteria you have chosen begins. You must select the ones that match best and then do your analysis of the included or selected studies.
See Quality asessement
Covidence
Covidence is a software program that can help with the selection (screening) process.
The program is useful for duplicate checking, literature sorting, quality assessment and data extraction when preparing reviews or for larger literature searches.