Portfolio is different post type built in our theme itself and it is not related to Jetpack portfolio.
Please follow this steps to create portfolio on your website:
1> Go to dashboard-> portfolio . Then add project there.
2> After creating project, go to Pages, add new page for portfolio. On the left side you will find template dropdown on left side inside page attributes section.
There you need to choose portfolio(Sortable) template.
if you got any problems on this, please let us know.