hard to play whats my basic rotation to kill stuff I also have the mana potion/hp potion so am I good for sustain?
That's a bit difficult to answer since its such a huge topic... for class guides i recommend the DK discord, as it will tell you a lot of info.
As I dont know what stance you chose, what level you are, which skills you have i cant really tell you what to use for killing.
As for sustain, in low end spots you will be fine with the inf pots, but once you move higher, you also need a frenzy elixir in order to make up for the lack of HP sustain the class has.