First you will need to use the ruler and the texta to mark out 3.5 cm around both the botom and top of the can as shown in the diagram.
Next you need to cut on the line to make two seprate parts both the top and bottom of the stove.
Now you need to make the inner layer of the stove this is the most important part of the construction, using the leftover part of can you need to mesure out 18cm lengh and 3.5 cm wide. then cut out the rectangle as shown.
Now you need to cut 3 tabs on the rectangle. then one joining tab on each end one the opisite way around as shown i the diagram. then put it together as shown.