RPG, Text Based Adventure - How to make monsters

[Althalus]

http://gameprogrammingpatterns.com/type-object.html
Using this tutorial but don't understand it, can someone please help me.

[TwilightSpectre]

What don't you understand? What do you have trouble with? For general monsters, its not too hard. Of course, the things that you'll need to store in data is dependent on the type of game you are making, such as (e.g.) sprites, AI, skills, statistics, etc.

[Althalus]

I don't understand how to add it into a main.cpp