Question: Listen From 00:56
[![enter image description here](https://i.stack.imgur.com/X68RF.jpg)](https://i.stack.imgur.com/X68RF.jpg)

The [E] part is in C Major key

and I can't understand the C#m7-5 chord at bar 3

what is this chord ? 

Where did it come from? and what is its function ?

Answer: 
I would read them both the same way. This is just differences in publishing style. My guess is that the first one is an older style.
A performer would play both versions the same way (you wouldn't accent the first note of every group or anything like that!). The differences are more for ease of reading / comprehension rather than performance instructions. 

The top example (Hanon) might be grouped as 8-note sets to show where the finger pattern repeats (you use 1234 5432 / 5432 1234 over and over again, just starting on a different note).

The second example makes it a bit easier to see where the crotchet beats are. (4 per bar). You could group them like the first example, but it might be slightly harder to read that way.