There is no reason to feel badly about admitting that you don't know about something; we all had to learn about this stuff somehow!
In your user directory (/home/yourusername), which is the directory you are placed in when you connect to your server via FTP or SSH, in addition to your domainname.tld directory/directories and your Maildir, you will find a directory named "logs".
Inside this directory you will find a directory with the same name as each of your domains. These directories contain other directories and symlinks to your http logs. In those directories you will find your log files (in various states and configurations). These are text and archive files containing log information from various times and in varying states for your webserver.
To review your error logs, find the appropriate "error.log" file (usually the most recent, if you are "actively testing", though it could be an older one if you are looking for an "older" error!) and view it (or download it for off-line viewing) to see what error messages were recorded for when you encountered the error. These are just text files that you can read with any editor.
What you are looking for is the entry that reflects the error you are receiving. I find the easiest way to do this is to run the program to get the error (and note the time), and then immediately inspect the last few entries of the log to identify the corresponding error message(s).
Posting these error message on the forum, or providing them to tech support) can greatly help in identifying the cause of the problem , in many instances.
There is a log more information about the structure of the information in the logs readily available on the web (just google for apache logs) , though most of the information in the logs is pretty self explanatory.