Workshops build your Units for Battle.
You build Workshops in battle to construct combat units based on the Knowledge that you've gained from Sacrificing High Priests. This knowledge carries over from battle to battle so that your diversity and power of units can increase over time.
Each Workshop can build only a few units so units put into production have to be choosen carefully.
On a new, Level Workshop there are two 'production Slots'. When a new knowledge to build is put into production, one of the slots is filled up. One chosen the production slot can not be changed.
When a workshop creates a unit, a Storm Power streem streaks from the workshop to the build site. When it combines with the proper Energy the unit will be created on the spot. However, if the Workshop is destroyed you will loose the ability to build anything that workshop was making until you build another workshop to replace it.