There are couple of options to achieve this –
1) Use [show_post_snippets] shortcode with post_type=portfolio. Just search in the forum for examples and you will find many.
2) If you are going to use SiteOrigin Page Builder(which I recommend), you can use Livemesh Grid widget part of the Livemesh SiteOrigin Widgets plugin. It is really easy to use and configure.
Once you setup the page with the gallery, do post the link here and we will provide you with a Custom CSS the easy way to disable the link.