Below you'll find the listing of where 120 and 140 mm fans can be installed in the case.
Note that 4x fans are included with the case (2x 120 mm side fans, and 2x bottom fans). The included fans have reverse fan blades, set up as intake fans. See bottom of this page for the specifications of the included fans. 
Note that the bottom fans have a maximum thickness of 25 mm. Anything thicker will interfere with the bottom filter.
For the side fans, note that anything thicker than 25 mm may require longer screws. The included screws are 27 mm long. For 27 mm thick fans, 30 mm long screws will suffice (30 mm are often the length of radiator screws).
Note that different builds may perform differently with the same fan setups, so testing to see what works best with your specific build is preferred.
Included fans in non-RGB version:
Included fans in RGB-version:
