Thanks a lot. I have some more doubts. We created k2 site which is https url and got ssl certificate too. Do I need to create site with this url in IIS ? Before installing k2 server. So that it appears under existing website ? 

And an application pool for that website in IIS. That's all needed for k2 server installation ? 

Setup Manager can create the site for you, but if you want, you can create the site in IIS first, and add a binding for the URL you want and set the SSL certificate. After that run Setup Manager and it should ask which site you want to use. Setup Manager should be able to pick up the site binding you are using.

If you have already created application pools beforehand, you can select which application pools you want to use, or you can let the Setup Manager create them for you. For application pools, I will recommend letting the Setup Manager create them for you unless you already have existing application pools in IIS from a previous K2 setup.