This is what I did find. Your case supports fans:
http://www.hardwarezone.com.sg/review-cooler-master-cm-690-iii-never-judge-book-its-cover
Front: 1 x 200mm fan or 2 x 120/140mm fans (1 x 200mm fan, pre-installed)
Side: 2 x 120mm fans or 1 x 180/200mm fan (optional)
Top: 2 x 120/140mm fans or 1 x 180mm fan (optional)
Bottom: 1 x 120mm fan (optional)
Rear: 1 x 140mm fan (pre-installed)
HDD Drive Bay: 1 x 120mm fan (optional)
Seems like there is bit mixen information. But case is nice so
Haha here is other one.
http://www.guru3d.com/articles_pages/cooler_master_cm_690_iii_review,2.html
Top: 120/140mm fan x 2, or 200mm fan x 1 (optional)
Front: 200mm fan x 1 (installed), or 120/140mm fan x 2 , 180mm fan x 1(optional)
Rear: 120mm fan x 1 (installed)
Side: 120mm fan x 2 or 180/200mm fan x 1(optional)
Bottom: 120mm fan x 1 (optional)
HDD cage: 120mm fan x 1 (optional)
Maybe 180 and 200mm fan have same size mounting points?
And drill is made for making holes so
😀