How can I programing a chatbot?

Question

AI's wich text with you

Answer 1

Start from begginers level
use if statements
if question == question1
print ans 1
else question == question2
print ans 2

or set more answers for same questions
and use random function ,so programme chooses the answer itself.

Answer 2

And a learning chatbot, wich learn new words when it text with you?