Creating a page with the same permalink as Simple Portfolio, then go to ‘reading’ settings, set as the front page doesn’t seems to work. Anyone?
I’m not sure if you still need help. The portfolio.php acts like WordPress’s page.php, you can customised the page you like. As for single-portfolio.php, it acts like single.php, you can customise the single post.
If you’re not sure what to do with it, I suggest you copy whatever that’s in page.php, do the same thing to portfolio.php. Same for single.php & single-portfolio.php. Hope it helps.