I want to create a network between me(Linux) and my friends(Windows). There is no way that I can connect them physically through a cable. The main goals are file sharing and remote administration. I want the process to be as easy and natural(drives appearing in my computer and stuff) on the windows computers.

I am a total noob in networking and I have zero knowledge about networks because I've always had a single computer so please give me something easy to follow. I am running Lubuntu 13.04 Raring.

I think you mean the actual connection is through the internet, but you want software to act as if the connection were through a LAN.

So one type of software you probably want is a "VPN". There are a few different freeware VPN systems available. I haven't used any of those myself. A google search for Linux VPN gives a lot of info on VPNs that include Linux support (almost any VPN includes Windows support).

A Samba server on Linux lets you expose Linux directories as "Windows shares". On a Windows system you can access a share directly or map it as a drive letter (some Windows programs work correctly with a share only when it is mapped as a drive letter. Others work either way).

A Samba client on Linux lets you mount a Windows share (on a different computer) as a Linux directory.

There is plenty of documentation available for Samba, that should be easy to find either in your own Linux distribution or online.

Which way? I expect you mean a Linux client for Windows remote desktop (Linux RDP), so you can administer a windows system from Linux. That software and documentation should be easy to find.

Remote admin of a Linux system from Windows has a lot more choices. The simplest is command line only (non GUI) using ssh (using putty or other ssh client program on Windows).

GUI remote admin of Linux from Windows using VNC or XDMCP is also possible.

I've given you the keywords that should be the starting points for google searches to get all the rest of your answers.