Buy ZCL in bittrex and transfer all coins to your private wallet. You need to have private key to get ZEN after 100k block hard fork. After ZEN will be forked you can just import your wallet and you will have the same amount of ZEN.

You need to install ZCL wallet to have private keys. You can download zclassic wallets from here:
http://zclassic.org/#getstarted
or
https://github.com/fxminer/zclassic-windows-wallet/releases