First of all, you need to know programming.
Then, you can go through those trading site to see if they provide any API for developer using.
Here is the API provided by bittrex:
https://bittrex.com/home/apiPlease read all messages here.
I have posted about my knowledge and skill.
Do you have experience of creating bot?
Hi friend. If you interested you can have a look at my topic. My bot is PHP based and all opensource.