>>1020745
It probably should have some sort of right click menu option to change permissions of the file. You'll want to set it to 755. I'm not sure if you can do that recursively for all files, so you might need to use ssh.
>Specially instance-config.php
For that you would probably want 700 for the user that runs php interpreter. If you manage local server then maybe limit ip range that can use ssh and ftp services, but I don't think there will be any security threads until you get a sizable amount of traffic. You will however be bombarded by chinks trying to exploit old version of apache and nginx so update those regularly.