403 can come from improper permissions or missing indexes option.
You should have all of your files in a folder like ~/domains/[your domain name]/public_html and maybe there are some subfolders, which is ok. All of the folders (domains, public_html, subfolders, etc.) all have to be permission of 0644 (owner read/write, everyone else read only) and folders must be 0755 (owner read/write/execute, everyone else read and execute).
If you want to go to yoursite.example (note that there's no folder name at the end) and you want to see a list of files in that folder, you need to add this line to ~/domains/[your domain name]/public_html/.htaccess (the file is a period, followed by htaccess) and add this line:
This will show a list of all the files and subfolders for your website. This is considered a mild security risk because you may have files that people shouldn't know they exist.
The normal way to do things is to NOT use Options +Indexes. Instead, create a file called index.SOMETHING where SOMETHING can be htm, html, or php. This file will show up either when you go to yoursite.example or when you go to yoursite.example/index.SOMETHING