When you have completed your search, you need to look through the hits to decide which ones you want to include in your work. When conducting a systematic review, the researcher examines all the hits. In order to satisfy the scope of your student project, you need to decide for yourself what might constitute a reasonable amount of hits to examine.
Start by reading the titles and abstracts to determine relevant results. If you are uncertain, read the entire text. A systematic search needs to be broad in order to capture relevant hits. However, this also means that a large amount of hits will be irrelevant.
In many databases you can choose to display the abstract in the list of results. By doing so, you can speed up the screening process and it will be easier to separate relevant from irrelevant material.