Hi,
as the words direct drive explain, the only way is to connect directly with two simple wires the + and - of the battery to the respective + and - of the led.
You have to think about, which battery you are going to use, because if you use a single 18650 or 17670 is safe, if you plan to use two 16340 or cr123a is not possible due to higher voltage of the two batteries in respect of the MC-E Vf.
Second for direct drive the best combination of the four die of MC-E is four parallel, in this case you need Vf 3.2 - 3.6 and VI of 2400 - 2800ma.
Resuming the best and esiest combination of a MC-E is 4 parallel die and a single 18650 battery.
Trustfire and Ultrafire 18650 protected battery have a current flow when fully charged at 4.2V of around 3.2A, that will decrease rapidly at 3.7V is about 2.7A, for experience Trustfire are better than Ultrafire, if you will use AW battery the discharge current will be higher.
The excessive V and I will be transformed in heat, but due to the generose body of the DBS, it wiil not be a problem.
I hope this can help you.
Ciao,
Marco