Got a Masterbuilt MB20077618 Analog Electric Smoker with 2 Smoking Racks, 30 inch, Black for fathers day.Have smoked in it couple times now but cant get a lot of smoke. Other smokers I see have vents in top and bottom my has none.Should i put some in? Tried last time leavening lid off chip box it smoked a lot better any help would be appreciated Thanks!