smoke and fire

im very new to blender and sometimes watch a tutorial and it doesnt work for me even if i follow the tutorial corectly.
for example i tried the quick smoke simulation. if i start it, i see smoke coming out of the objekt but if i try to change to smoke + fire nothing happens and if i change back to smoke only nothing happens too. any idea what i could do wrong?

It could be many things, best bet it to post a blend file where you have it not working and a link to the tutorial you are trying to follow and I’m sure someone can quickly tell you where you are going wrong.