You will not be able to do that in out of the box Qlik Sense.  If you can you will need to create a mashup.

The best you can do is have the first sheet be the home page.  You could add buttons from an extension to navigate to the other sheets from here and then back to the home page from the other sheets.  The only way to have the home page open is to have the user use the URL directly to it instead of going to the hub first.