1. first of all, on the notes you give to download 2 files and add them on our initial folder, when i click, i download only 2 file, not two. How to get the second?

2. I added the code to the head.php

Seems to doesnt work. Needs maybe the second missing file?

@KaloSex
I see 2 files in directory of archive:
https://github.com/OneSignal/OneSignal-Website-SDK/releases/download/https-integration-files/OneSignal-Web-SDK-HTTPS-Integration-Files.zip