as far as i know, you need to import in a bch wallet like electrum.
I have found a topic with the step-by-step instruction how to claim your BCH.
https://bitcointalk.org/index.php?topic=2078292.0or, here another way:
This is simple:
1- Export 12 word recovery phrase from your current Blockchain.info Bitcoin (BTC) wallet A
(which did have some BTC on August 1!)
2- Create a new Blockchain.info Bitcoin (BTC) wallet B
3- Transfer ALL bitcoin from Bitcoin (BTC) wallet A to B
Wait for minimal of 2 confirmations! Your wallet A is now EMPTY.
4- Create Bitcoin Cash (BCH) wallet at BTC.COM
5- Import the bitcoin cash with 12 word recovery phrase from wallet A (bullet 1)
(no risk for your bitcoin, since your wallet A is now empty and your bitcoin now is in wallet B)
Enjoy!