How does braille reading work? First follow the lines.

Position the index fingers at the beginning of the first line. The 2 index fingers have the primary function of searching and decoding: this is known as two-hand reading. Make sure that all the fingers, except the thumbs, are resting on the line to be followed. 
The palms of the hands must not touch the page, only the fingers are in contact with it. 
Be careful not to apply pressure to the points: the pressure should be very light.

Another pitfall to avoid: don’t move your index finger up and down. On the contrary, it crushes the relief of the dots and the nerve endings, and wastes a lot of time. The size of the braille cell has been chosen to be perceived in its entirety by the fingertip. There is therefore no need to move up and down.

Students need to practice sliding slightly from left to right without stopping, without returning to the cell and without moving up and down.

There are at least 3 different techniques for reading braille. 

Transcription

To read in braille, you will need to use
all your fingers except the thumbs.
The two index fingers
will be the one reading the characters,
but all the others will help to follow
and track the line.
You will read, decipher the characters
with the pulp of your fingers,
and this part is really great
and you need to have a very light touch,
very light, not to stick your fingers.
First technique:
You will have all your fingers aligned.
The two index start at the beginning
and then you will slide to the right.
The picky right finger will tell you
that the line is finished.
There is no more characters,
so you slow down
and then when you will go back
to the beginning of the line,
the left picking fingers will
tell you where the beginning is
so you can slow down a little bit.
There are several techniques
to read in braille.
One of them is when you place
all your fingers,
index at the beginning, then you track
the line left to right.
When you are at the end, you go back
to the beginning
and then down to the second line.
You track to the right.
All fingers go back down to the next line.
Another technique is when you start
still the same, the two index fingers
at the beginning of the line. You track
and read from left to right.
When you are at the end,
the right hand stands
and the left hand goes back
down to the second line, and this right
hand goes to the second line too.
Then the two hands slide to the right.
The right hand stops.
The left goes back down
and the right comes again.
Another technique is
when you start the same two index fingers,
you slide, you track the line,
and when you reach the middle,
the right hand goes right and the left
hand goes left until the beginning.
So you have your right hand
at the end of the line, your left
hand at the beginning, and then the left
hand goes down the second line.
The right hand go and join the first one.
So you start again.
The two fingers
goes till the middle of the line,
then the right hand to the right, left
hand to the left,
left hand down to the next line
and the right comes, and so on.

1st technique, often used at the beginning of the learning process:
Slide both hands side by side to the end. When the right index finger reaches the end of the line, return to the beginning of the same line, keeping both hands side by side. 
When the left index finger reaches the first character on the line, move down an imaginary vertical line to the start of the next line of text.

2nd technique:
Slide both hands side by side to the end. The right index finger remains in place, positioned at the end of the line, while the left hand returns to the beginning of the same line. The left index finger moves down and positions itself on the first character of the 2nd line. The right hand detaches itself from the text to take a shortcut and rejoin the left hand. The 2nd line can now be read.

3rd technique: 
Slide both hands to the middle of the line. While the right hand continues to slide to the end of the line, the left hand returns to the beginning and moves down the line. When the right index finger marks the end of the line, it takes the shortcut and joins the left hand, which is positioned on the new line.

In order to develop the reading technique comfortably, it is important to ensure that the child is sitting properly and that their posture is functional.