Faces don`t look like transparent

Support Materials and Textures
1

I have a truck model and the windows faces look like opaque regardless I enabled Transparency parameter in Material section:

Why does it happen?

Download the model and the texture:
https://ufile.io/hr6m9ewz
https://ufile.io/2dl9mdhc

2

You can see the alpha below.
Reduce the amount and it is become transparent.

3

Thanks for an answer! I`ll try out that.

4

I set Alpha to 0 value and it doesn`t change anything. Also I noticed if I create from those windows a separate object and select that it will become to look like transparent, but if again unite to the basement it will become opaque again.

5

Make it separate and parent them, with (ctrl+p) if nothing else working.

6

N%C3%A921414n
N%C3%A921414n1920×1080 245 KB

I downloaded the file. For me it works.