Simply append (file/append) the planes from this blendfile ("bge_firesmoke_nm8.blend") into your scene and adjust its materialparameters in the nodeeditor.
The animation is achieved by the use of two materials. one which stores keyframes, and one that uses the keyframed animation as input for the nodes. Also to see the movement in the game the animation needs to be invoked by a logiceditor setup. all this is already setup in the planes of the blendfile, so it is really the fastest way to simply append the planes.

Flame material:
-turbulent  this parameter controls the distortion of the flame.
-scale    this parameter controls scale and speed of the flame.

Smoke Material:
-color1  sets the maincolor of the smoke
-lit sets the illuminance from below and sides. usually an orange flamecolor.
-turbulent controls the distortion of the smoke
-scale sets the scale and speed of the smoke
-shade darkens the smoke to look bulgy
-bump fakes a bumplightning onto the smoke

use several planes at different angles to achieve a volumetric effect.