Starting Web Press

I haven’t started yet but I need to understand how to do this. I have a web site and would like to create a new web site with Word Press and eventually replace my current web site. I host my web site with GoDaddy.com and I have read that I can connect to Word Press via GoDaddy or do the quickstep download directly with Word Press. What happens if I do the download with my GoDaddy host? Does it interfere with my current web site?
What are the steps to creating a Word Press web site and design.
I am in the dark about this.
thank you,
Nan