Finaly got how this game works.
Note:
At the opening the main character (the player) explains the girl, Kusuda Maki, is his niece who left her parents home and is now lodging in his house.
I coudn't understand why in the op (apparently some disagreeing) but, throughout the game, it seems to be due to the school she's attending being far from her parents home.
End of Note:
(I've made some changes here and there and added some info just to hopefully make things easier to understand) - SwiftKit
The Talk (2nd. from the top on the right menu) button allows you to pick among 3 independent topics:
Choosing any of those will move only that topic ahead eventually triggering the girl to talk back. That may also enable sub topics related to the active main one.
Depending on your answers and
Maki's fondness gauge, you may be rewarded with either a
red heart ❤ or
blue diamond 
The hearts/diamonds will appear in between the 2 vertical bars.
The 2 Vertical Bars are her
Arousal(LEFT) and
Obedience(RIGHT)
Maki's fondness gauge is the gauge in-between the 2 vertical bars
Tip:
Looking (1st. button on the right menu) at the girl's face tinily boosts the fondness gauge (Can't understand the logic in that though).
If you want 3 hearts, take your time maxing (all the way to the right) Maki's fondness toward you.
Okay,
For anyone confused on the new JSK game, no worries, I got you fam. With help from Decagem, I've wiped up a small breakdown/guide to get you started.
First off, read the quote above to get the overall idea of the game. After that, we are ready to get started.
So First off, you will start the game in the default mode. We are going to call this
STORY MODE 1, and the name of the game is to unlock the other story modes
which will in turn unlock the different endings. This next part may get a little confusing but once you play the game a bit and start to get a feel you will pick it up with ease.
Below will be 2 easy guides to unlock
STORY MODE 2 and
STORY MODE 3 from playing
STORY MODE 1
SIDE NOTE: some dialogue choices will trigger grey dialogue boxes to appear underneath the 3 talk choices. These will be where you will pick up
hearts ❤ or
diamonds 
in the first story mode
Unlocking
STORY MODE 2
:
(Anytime she talks to you, the dialogue pops up, choose the 3rd choice)
Talk: Choice 1
Talk: Choice 1
She talks to you: Choice 3
Talk: Choice 1 (
Triggers first grey dialogue box)
Click the grey dialogue box:
Choice 1-
Triggers another grey dialogue box
Click the grey dialogue box:
Choice 2-
Triggers another grey dialogue box, same place
Click the grey dialogue box:
Choice 2- Triggers first
Blue Diamond
Click grey dialogue box again: (REPEAT this step twice for the final 2

's)
Choice 2-
Blue Diamond

[Once you have all 3
Blue diamonds
just keep exhausting dialogue choices until you get
a
red dialogue box to appear. Normally, clicking this dialogue box would end the game
but with 3
Blue Diamonds 
you will unlock
STORY MODE 2 upon click it]
Unlocking
STORY MODE 3 ❤:
(Anytime she talks to you, the dialogue pops up, choose the 3rd choice)
Talk: Choice 1
Talk: Choice 1
She talks to you: Choice 3
Talk: Choice 2
Talk: Choice 2
She talks to you: Choice 3
Talk: Choice 2
Talk: Choice 2
She talks to you: Choice 3
Talk: Choice 1-
Triggers first grey dialogue box
Click the first grey dialogue box:
Choice 1
Click the first grey dialogue box again:
Choice 2 - Triggers first
Red Heart ❤
Click the grey dialogue box again:
Choice 2- Another
Red Heart ❤
After that she will try to talk to you:
Choice 3- Last
Red Heart ❤
[Once you have all 3
Red Hearts ❤ just keep exhausting the dialogue choices until you get a
red dialogue box to appear. Unlike unlocking
STORY MODE 2 this will require you to run
through more dialogue. Don't fret, just keep talking till the
red dialogue box appears.
Clicking the
red dialogue box normally ends the game, but with
3 hearts ❤ you will unlock
STORY MODE 3. congrats]
I Know that is a lot to take in, but I believe it's a good chuck of info to help anybody out with the game. I'll probably make an update post when i figure out the rest of the game and endings but
I believe this is enough information to figure out the endings for yourself with a little messing around. If you need more help there are already posts above with guides for some endings already
check them out, they bossed it

GOOOOOOODDDDD LUCK
