ISSUE:

Hello, can someone explain to me why the configurations are those is that I'm trying and they don't come out like that. Thanks in advance!!

Knowing that the Ph and Boc groups are these:

Hello, I leave you the following page in which Germán explains the Fischer projection very well.
If you realize the substituents that come out horizontally from each carbon are wedge-shaped (out of the plane). As in all asymmetric carbons we have hydrogens (H) as a wedge, this changes the configuration that the carbon in question would have. I will give you an example: In the carbon above, the order of priority would be a-NHBoc;
b-CHOH; c-CH2OPh; dH. Under normal conditions, the rotation would be clockwise (R) but as I have commented before, since the hydrogen is a wedge, the configuration (S) is inverted. I hope I have helped you, regards.

Germán's page: www.quimicaorganica.org/estereoquimica/5...cion-de-fischer.html

Exactly what I don't understand is why it is b-CHOH;
c-CH2OPh and not the other way around. Thank you!

Let's see if that's how you see it better:
To assign an order of priority to the different substituents of the carbon in question, you have to look at the groups that accompany them.
Again with the carbon above with S configuration: NHBoc group would have the order a due to nitrogen, which has a greater preference than the two carbons, and hydrogen.
- If we look at the CHOHC to which I have given the order b above the CH2O , if we look at the substituents that accompany them, being for the carbon that remains on the left: CHHO and for the carbon below : CHOC , if you look at both H and O is common on both carbons, the preference of one over the other is given by the presence of the C over the H
- Finally we assign the letter d to the H on the right that It would be facing up as you could see on the page that I proposed to you.
The turn a - b - c - d would therefore be clockwise (R) but due to what was said in the last point, the S configuration is finally obtained. I
hope I have helped you!

now i've seen it!
I forgot the detail that compares the groups directly attached to the carbon that we are comparing THANKS