to claim each of these new coins they keep creating these days and call them bitcoin forks, all you need to do is download the wallet they are releasing. in some cases this may be very risky since most of these projects are pretty unknown.
in case of bitcoin cash, go to
http://www.electroncash.org/ and download the wallet.
i suggest installing it away from your Electrum wallet because it will copy all your electrum wallets into its own directory and you may not want that.