How do I do this? Do I have to be a vampire Lord or what?

It's a master level conjuration spell so no, you don't need to be a vampire lord.

Hope that helps!

Like Personalblaze said its a Master level conjuration spell. If you're familiar with raising the dead, its like that but your raised ally has no duration. Meaning, its a permanent raise dead spell. If you fast travel, your thrall will follow you. If your thrall is killed in battle, it wont crumble into a pile of dust. You can re-raise it. But you need a very high conjuration level and need to complete a special quest at the College of Winterhold.

Do it!

Very fun. Also, you will begin to have favorites... I keep a whole pile of them in the basemant at Heljarchen Hall. Anchors in the ones I really like!

Does this make me a bad person?

edit: the spell requires bucket loads of magicka, however... if you want to use it, you will have to start leveling up your magicka pool early.

Alright magic hasn't been my thing so say I become a vamp Lord do they have this ability and can I use it without leveling magic and what not

Nope. As others have said, it is a master level conjuration spell. Not related to being a Vamp Lord at all.

edit: http://www.uesp.net/wiki/Skyrim:Dead_Thrall

So could a vampire lord who is a master of conjuration use this spell?

Lol. For some reason that reminded me of the gas station scene from "No Country for Old Men."

Ha! A little darker, but yes!

Vampire lords cant use dead thrall.