There are not many possibilities yet to buy Bitcoin Cash directly.
You can check on
LocalBitcoinCash.org if you have a seller in your country.
You could also buy a different coin and then immediately convert it to Bitcoin Cash.
Because transaction times are long and fees high I would not recommend to buy Bitcoin but for example Litecoin or Ethereum.
Once you have those you can convert them easily using
Shapeshift.io (the quick option is the easiest way)