How to make an enemy follow a player using a navmesh

I have a game where the floor is all one object, I generated a navmesh and I attempted to replicate the example but without it working. Can someone please tell me what steps I should be taking such as what gets a navagent (if anything) etc.

My enemy is a mesh of a person with an armature attached and rather than in the example where you click on the ground and it moves there, I want to be able to be moving around with the enemy always following me.

Urgent help is appreciated! Thanks in advance

Time to upgrade the navmesh example, will add something which follows the player.