1. Install Ubuntu 16.04 LTS
2. Install latest AMDGPU-PRO driver (check if your card supported by driver)
3. Download bins zcashclient-0.2.2.zip
4. Edit config.txt, put your wallet and try to change instances 1 or 2
5. Launch silentarmy bin
6. That's all!

RTFM!

P.S. Got on my 2x RX 470 - 70 sol/s