If you would like your simulation that was created in your main account to be accessed by certain subaccounts, there is an easy way to do this.
From your dashboard head over to the Manage Access page
Select the "Sims" tab from the top.
Find the sim you wish to share with a sub-account and select the following icon at the bottom
Check the "Link" checkboxes for all sub-accounts you wish to link this sim to. These can be removed at any time if needed.
After this, the sim will be available to all users with a management-level role within that selected sub-account. Do note, any changes made to the linked sim will affect the main accounts sim too. If you wish to make changes that only reflect in the sub-account version, duplicate the main account's sim first, and link that duplicated version to the sub-account.