I feel like all of you failed to note exactly what the OP was confused about. Namely, how to actually EDIT the file (the only thing that logically makes sense when he says "enter the file"/"come in to the file"). Which, ironically enough, is not explicitly said in either the wiki or the blog post linked to above (someone needs to fix that. A lot of the documentation here assumes you know the most basic stuff about linux norms and common linux programs. But those of us who need the documentation most usually don't, at least not when we first get here).