Research may only be done after you have unlocked and built the Academy, which happens after you reach level 8. After building the Academy, the blue "laboratory beaker" icon will appear on the bottom menu, allowing the player to unlock new buildings under the Build menu by paying the Research cost. (This also produces Fame and helps you reach higher levels). You may also upgrade the Academy itself through the Build menu to unlock higher level Research.
|Name||Unlocked at Level|
After completing the Research, you will have to go back to the Build menu to find the building upgrade you've unlocked and Build it. It will upgrade the currently existing building on the map.
Researching upgrades may be done out of order, but there's no advantage in this since upgrades must still be built strictly in order. So while you may research Royal level research before Village or City research levels have been researched, you can't actually upgrade the building from Village directly to Royal. You may not skip in-between levels when building.