Multi-fuel stoves are fitted with a variety of controls - the most common of which is a damper fitted in the stove outlet where the flue pipe is connected. (Please note - not all stoves have a damper fitted - however, dampers can be purchased as an optional extra if required).
The damper will increase/decrease the chimney draw depending on how far open / closed it is. The bottom spin wheels/slide ventilators allow more/less air to the stove, regulating the burn rate. Combining the use of these ventilators will allow full control of your stove, It is purely the experience of using your new stove that will give you the best results. Remember that different chimneys draw differently and only time will familiarise you with your stove and the way that your chimney draws.
The bottom air controls are generally not required when burning wood, as you don't want air underneath the fuel
If your stove has a spin wheel/slide ventilator above the door then it has an airwash system (method of keeping the glass clean). To operate, the damper must be fully open with the bottom controls CLOSED. Again, only experience will give the best results.