Kickstart shows "NOT FOUND"

[weiyknow]

I have experimented kickstart following the instruction from open data project.
I saw "Page not found" 404 error after activating the kickstart plug in. I am not sure where I should put the dataset. I tried two different ways. 1. I add data set from dashboard. 2. I put data.json in the same folder as plug in. Can you provide more detail description how to configure? Thanks.