HI
on a fresh installation, impossible to me to install modules or themes
"Failed to install one project, Permissions are not set up properly."
here is my /var/www/html directory
l# ls -al total 9308 drwxrwsr-x 9 root root 4096 Aug 10 00:13 . drwxr-xr-x 3 root root 4096 Aug 9 18:13 .. drwxrwsr-x 2 www-data www-data 4096 Aug 9 18:37 backdrop -rw-r--r-- 1 www-data www-data 9461955 Aug 8 00:39 backdrop.zip drwxrwsr-x 9 www-data www-data 4096 Aug 9 18:31 core drwxrwsrwx 8 www-data www-data 4096 Aug 10 10:50 files -rw-rw-rw- 1 www-data www-data 578 Aug 7 22:39 index.php drwxrwsr-x 2 www-data www-data 4096 Aug 9 18:31 layouts drwxrwsr-x 2 www-data www-data 4096 Aug 9 18:31 modules -rw-rw-rw- 1 www-data www-data 3978 Aug 7 22:39 README.md -rw-rw-rw- 1 www-data www-data 1216 Aug 7 22:39 robots.txt -rw-rw-rw- 1 www-data www-data 15990 Aug 9 19:09 settings.php drwxrwsr-x 2 www-data www-data 4096 Aug 9 18:31 sites drwxrwsr-x 2 www-data www-data 4096 Aug 9 18:31 themes
So, what I have to do ?
This is not my area of expertise, however I can point you at some documentation on the issue:
https://backdropcms.org/file-permissions-and-ownership