Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This is a DPS build for ashe that focuses on attack speed.
Don't be afraid to change the order of items if you feel you need to depending on who your fighting.
For example if your fighting an invisible champion you might want to get Oricale's Elixir at some point to stop any invisible ganks taking you by suprise.
Also you might want to get a health potion at the start but it's up to you.