You don't need anything but the game, a computer, and a connection to make a server. If you want to make your own server with you playing in it you can create your own listen server and dedicated server from the main menu. It don't tihnk it is totally advised though to make a dedicated server you yourself are playing on. To make a server just create a sever from the option, pick the options you want, and make sure to tell people the IP to join.
To join through IP find it on your computer. There are several sites that can tell you your IP if you don't know. Just type in: What is my IP at any search place and you can get it. Then tell everyone you want to join to go to favorites instead of internet, click new favorite, entier in the IP using the periods and they might need your port number too, then click to join. Since it isn't broadcasted to master lists when it is a listen no one should join.
I would also advise getting something like the Jedi Academy mod to help control people in your server. It comes with a list of commands you can do from kicking to muting to imobilizing people.
Concerning the connection the better the connection the better the people playing from your computer will be able to play. If there isn't enough memory or bandwith or other factors they will experience lag. Also having them close to you would help too. EX: If you started one in Washington and everyone lived in NY then they would have higher ping than someone in California most of the time. The more central the server computer is in regards to location to everyone else the better the ping for everyone will be.
If you have any direct questions feel free to ask.