The Cost Structure are the expenses of your business.
Together with the Revenue component you can estimate the profitability of your business.
At this stage you need to create the confidence that your cost and revenue are in balance.
Ask yourselve what the biggest costs drivers are for your business.
Look at your Key Resources and Key Activities and determine the most expensive parts
What cost is equal all the time and what cost changes if you produce more?
Fixed cost can be rent, maintenance and licence fee.
Ask yourself what would happen if you would triple your sales? The cost that increases is your variable cost.
Look at the Key Resources and Key Activity to verify if the main the cost drivers are identified.