How to add more sections ?

I’m not the designer of the theme but that this isn’t possible without extensive modification to the code. You would need to code individual options for each area that you wanted to change.

The only potential way to do this is to go into the code and copy the section that you would like to duplicate and paste it in the position you would like it. You’d then need to change the id of the pasted section to what you wanted e.g. Portfolio. You would then have to take out the variables and replace them with the content you wanted to display. To get the navigation working you would need to add the link to that section.

A lot of work, but possible.