In the first picture the tubes are hooked up to the two graphic cards using GPU water blocks.
And no.. it's not hooked up to hard drives.
Hard drives never get hot enough to even need air cooling really.
Most cases will have the front intake fan blowing over the hard drive cage though, this helps cool hard drive arrays as having 2-3 on top of each other makes the top drives rather hot.
Just a side note.. and I don't want to offend with this..
But if you didn't know what a GPU block looks like, or whether 'liquid cooling a hard drive' would be useful, a liquid cooled build might be a bit demanding for you.
In todays market there are many single solutions for water cooling. The Freezone Elite has the best temps of any water cooling system I've ever seen.. and it's just a plug and play job.
Hope this helps.