Server FTP File Sharing

Question

How do I activate the VPN, FTP, and File Sharing on my server? Also, is there a way to access my server from another machine without using my IP address without port forwarding and/or registering an internet host name? Also, I have another post on how to use VPN on server, found here: https://discussions.apple.com/message/22026213#22026213
Please answer to both of these posts, I really want to make this server thing work.

Answer 1

Do you know how to connect to my server without knowing the IP of the host and without registering for a internet domain name or port forwarding?
This is absolutely not possible.  To connect to a remote server, somebody somewhere has to enter the identity of the target server among the billions of net-connected devices. 
Now can that information be loaded into a client device, and can an end-user avoid having to know about these and other details of networking?  Sure.  What's variously called "provisioning" is a common approach used here. 
There are other approaches available which can be useful on different and often on smaller networks, such as what Apple calls Bonjour; variously known as multicast DNS services and service discovery.
There are other potential solutions.
Also, does anyone know how to specially protect a folder in File Sharing?
Sure.  Usually with what's called a file mode or protection mask, or via access control lists. 
Whether the protections are effective depends greatly on who you're protecting against, and how the files are being shared.
My server at school only allows certain users to access certain folders, but when I connect to my server I have the same username so I don't need to enter any kind of log in.
Why not ask the folks that run the server for information?  You are affiliated with a school, and the purpose of such institutions is to learn, after all.  Ask some questions of the folks that are running the configuration you're familiar with.
If it's a typical educational configuration, there'll be a "directory" — Microsoft Active Directory is common, though there are others — containing information mapping your identity to what you're authorized to access or do, as well as a variety of other information such as your identity and your email address and which mail server you're using for accessing your mail. 
Can you password protect the folder?
Directly?  Not really.  Details here depend greatly on the operating system and file system involved, and on how the files are being served, and how the files will be accessed.   File-level encryption can be used, and web servers can protect folders, and various operating systems including OS X support what are called encrypted disk images.  Web content management systems can also provide access controls, too.
Rather than continuing this blizzard of questions, please consider providing us with some background on the problem you're looking to solve here, and some of the general requirements.  There can be many potential solutions, and even more wrong solutions.  With some idea of what you're looking to do, we might be able to give you something more specific to look into.
As for learning more about OS X and OS X Server and server networking — all of which can provide some background and can introduce a number of these general topic areas — see the OS X Server documentation, and — for yet more detailed information — see the 10.6 server documentation that's linked from there.  The older 10.6 OS X Server documentation was much more detailed.