To enable the comments section on Jupiter you need to take these steps.

Enabling comments

1From Theme Options, go to Global Settings > Site Settings and enable the Comments on Pages option.

 

2Go to the page on which you want to enable comments, and from the top right section, click on Screen Options and check the Discussion checkbox.

Comments not showing

3A new Metabox will appear at the bottom of the screen which you can use to enable comments:

Comments not showing

Now the theme will show the comments section on your pages.