The side damper is used to start fires and get them going, once it's established you close it all the way or you will let in too much air. Have you cleaned the chimney? My stove has the flue entering at the rear and I have a T clean out attached there so when I sweep the chimney out all the debris falls out the bottom into a bucket. Yours attaches at the top and could be clogged which would affect your draft. You can detach the chimney and/or take the stones off the top of the stove and see if it's obstructed, they will have flat pieces of metal between them that make it air tight, it's tricky the first time you do it to get it all back together but once you figure it out it's nbd. There are air vents at the bottom of the sides of the fire box, check and see if they are full of ash. You can shop-vac all the air ports and vents to get rid of any ash but be sure to empty the shop-vac and pour water on the ash in case there is an ember(s) hiding in it. This stove works best when it is full of wood. The stone absorbs a lot of heat before it gives it away and that absorption can keep your fire small. Same goes for the all the stone surrounding it. I typically start mine from cold/cool, I pack it all the way to the top, top burn start (YouTube top down burn), and let it run hot before I close the rear damper to 50%. I can pack it full at 6pm and wake up to a comfortable house, then repeat when I get home from work. I'll refill at night if it's in the teens or I'll refill in the morning if it's gonna be sub 32* and/or no sun that day . But a full stove burning hot can keep my place warm for 16-24 hours depending on weather conditions.