Dude, I don't know, if you're getting stumped on this fairly simple stuff, I don't know that you should be running apache since it can at times be non-sensical and is kinda a pain to setup/maintain.
Certainly this machine should not be globally-accessibly (read: no firewall in front of it or, even if there is one, ports 80 and 443 etc. forwarded to it), at least until you're a bit more comfortable with administering the system, since it would only be a matter of time before some script kiddie came across your machine and took advantage of some vulnerability or misconfiguration.