Detailed steps to change the Fire settings from Auto->Manual.

  1. Access Settings (a small gear icon on the left top corner under profile) on home-screen. 
  2. Select 'GAME' option. 
  3. Change the 'SHOOT' option to 'MANUAL' or 'AUTO' according to preferable choice.

Settings can also be changed from ingame:

  1. Proceed into a match.
  2. Select Settings (gear icon). 
  3. Change 'SHOOT' option to 'MANUAL' or 'AUTO' according to preference.