Undock the toolbox panel. Click on emitters in the upper listboxand particle emitter in the lower listbox.
Click at a location in the space to create a particle emitter. Right click when done.
Click on the Play button to see the particle emitter working.
Undock the property editor panel.
Lets get smoking
How much smoke how quickly?
From the right listbox of properties for the particle emitter, expand the Continuous property then click on ConstantPulse. Under the ConstantPulse property, increase the frequency property by clicking and dragging (scrubbing) the roller to the right.
Click the selected tab at the bottom of the property editor panel to go back to the particle emitter properties.
How big are the puff particles?
Click on Dimensions and adjustSize roller to the desired amount.
Increase the Scale in slider and keep the Scale out slider at zero.
How how transparent is smoke?
In the left listbox of the panel, ensure the ParticleMaterial is expanded then click the Translucency item underneath it. In the right listbox, click on the Blend Mode property and select Alpha blended.
Smoke is often a blend of various colors not just one color.
Now click on the Diffuse item from the left listbox. In the right listbox, click on Diffuse Color Source and select Material + vertex color.
Click the Menu button (triangle)on the right of the Color property and select +ColorComponentsAttribute.
Expand the Color property item. Under the ColorComponentsAttribute property, click the Menu button on the right of the Brightness property and select +NumberNormalDistributionSamplingAttribute.
Click the Menu button to the left of the Brightness property. Ensure the NumberNormalDistrubutionSamplingAttribute property is expanded and move the Standard Deviation slider to the desired value. Best to change this while in play mode. That way you can tweak the variance in real time and see your outcome.