Hello, where does the AMD RX470 driver download?
If you got a RX 470 don't mine ZEC with it. The max speed you will get is like 280hs or so.
ZEC is geared towards older GPUs like the Radeon 7950/7970/280X or some types of Nvidia GPUs
With your GPU you are better off mining something like ETH or ETC you will make more.
Just go to What to mine and put in your GPU there and mine what is most profitable.