I'm sorry, but I'm having a hard time figuring out what you are asking, but maybe I'm just slow-witted this morning.
The "full path" is really nothing more than a completely (unambiguously) described location of your file. For instance, if you have a file located in the "yourdomain.tld" directory named "myfile.php", then it's full path on DreamHost would be:
How you "enter" that (in quotes, without quotes, etc) depends on where you are entering it and what you are trying to do.
What are you actually trying to do? From your post, it looks as though you might be trying to create a cron job or trying to configure an application, but I can't tell.
Generally when an instruction talks about a "full path", or a confuration file needs a "full path" indicated, it helps to understand the context in which the question is asked.
If you can provide a little more info, I'm sure someone here can help you - they may just not have answered because they are confused by your post (as I am ).
To get better answers to your questions, you might find it helpful to look at "How To Ask Questions The Smart Way".