On closing an opportunity and selecting the Contracted field a new contract is automatically generated. This new contract is automatically assigned to the account in question and subscription products are added. Is there anyway to ensure the assets are automatically added to that contract?
Assets are associated with a contract only if the subscription product they are related to is configed as "Percent of Total" under the field "Subscription Pricing". The "Subscription Category" field also should be configured if you have different subscription products for different asset products so that the assets are associated with the correct subscription.
There is more to it, but hopefully that gets you moving in the right direction.