Well, the first unit you will make is the Paladin which you can produce in the Statue. You can build the Statue in the Village Headquarters.
The second unit you will produce are the spears. You'll need a lvl 1 Barracks to make them. To build the spears you'll need a lvl 3 Village Headquarters.
Later on you'll have to research units in the smithy.
For even more information check the
help pages and press whatever troop you want to get information about. You can also contact me in-game for further questions.