Page Builder

A few questions here please.

I’ve installed the Page Builder plugin and it only works on the home page and contact page. How do I get it to work on all the other pages?

When I make a new page it has a Leave a Reply form on it. It happens on all the new pages I make. How do I change this?

How do I remove the sidebar from the Homepage? I’ve made it a full with page but it still shows up?
Vantage theme.

Thank you in advance for your answers.