There are 2 ways a vacancy is created in altHR. One is when the employee is terminated. The position that they held would then register as vacant in the system. The second is to create a new one directly.
To create a new vacancy go to People > Organisations > find and select the organisation where the position will be in > select "Positions" > click "Create New Position"
Fill in the relevant details of the new position and click "Submit". A new position has been created in the account.