How to write and equation to find the answer

If Karen works 1 hour, she prepares 2 kg of dough.
If Karen works 2 hours, she prepares 2 kg + 2 kg of dough.
Maybe you can see where this is going.
If Karen works 3 hours, she prepares 2 kg + 2 kg + 2 kg of dough.

If Karen works h hours, she prepares 2 kg + 2 kg + ... + 2 kg of dough, where the number of instances of 2 kg is equal to h.

Early in your math career, you learned that repeated addition can be represented by multiplication. That is, when Karen works 3 hours, she prepares 3*(2 kg) of dough. It is not that big of a stretch to see that when Karen works h hours, she will prepare h*(2 kg) of dough.

Karen's output = h*(2 kg) . . . . . . an equation for finding the amount of dough

You are asked to solve this when h=5.

Karen's output = 5*(2 kg) 
Karen's output = 10 kg

If she works 5 hours, Karen can prepare 10 kg of dough.

Are you trying to figure out the volume?