Can't deal with Google drive (backup and sync from google)?

Question

Google

Hello!
I can NOT deal with Google Drive, or rather with an application for synchronizing with a computer backup and sync from Google. Why they released such a crazy version is unclear.
Firstly, it is not clear why I initially had a disk storage capacity of 115 GB, although the default is 15 GB and I did not buy anything.

image1

I downloaded this very backup and sync from google application to my computer, although I don’t fully understand what it is for. I downloaded just to make it more convenient to download files uploaded to Google cloud (for example, clips) - through synchronization applications it is always faster and more stable. That's all.
But for some reason it doesn't work. Here I have it installed -

2

Here is the google drive folder on the desktop -

3

But there is no synchronization. I upload large files to Google drive and they are not on my computer. Although good. Why is there no selective synchronization as in normal clouds like Yandex?