There are few ways to change your .HTACESS file setting to 766. For the following example, I am using SmartFTP and Filezilla for your reference.
Using SmartFTP Step 1: Login to you blog using FTP program.
Once you login in successfully, you will see the directory listing.
Setp 2: Look for public_html folder or /www/ shortcut and double click on it.
Step 3: Look for .htacess file, hightlight it and right click on your mouse and select Properties / CHMOD.
Step 4: You will see the small menu pop up and change the number to 766 and press OK.
Using FileZilla Step 1: Login to you blog using Filezilla program
Once you login in successfully, you will see the directory listing
Setp 2: Look for public_html folder or /www/ shortcut and double click on it.
Step 3: Look for .htacess file, hightlight it and right click on your mouse and select file attributes.
Step 4: You will see the small menu pop up and change the number to 766 and press OK.
That's all, you have changed the setting in
.htacsess file and you can repeat the same steps for change any folders and files setting.
P/S: Assume you knew how to access to your host account from FTP program.