Basic question, need help

1. See 2.
2. Create an index.html file in your html editor and link your other pages from it. Then upload it to your web root. Go to your url http://yourdomain.com/ or http://yourdomain.com/index.html and this will load the index.html in your browser. You can then see what every one else sees on the Internet and will be able to spot which tags are giving trouble and, using your http editor, fix them then upload the fixed pages to your web root overwriting the bad pages. This technique is better facilitated using your favourite ftp client not cPanel file manager, some may dispute this.

web root = /home/useryou/public_html/hereisyourwebroot.
http://yourdomain.com/hereisyourwebroot

Do 2. first then you may not need to fix 1.
HTH