Navigate to Dashboard -> Portfolios -> Add New to see the portfolio edit screen. From here scroll down until you see the "Portfolio Options" meta box.
This meta box holds all of the options for your portfolio post such as the portfolio date, link, teaser, etc etc. You will also see all of the regular post options here for sidebars, backgrounds, etc etc.
Other meta boxes that display when editing your portfolio posts are the SEO options.
The text you input here will display beneath your portfolio title when using the portfolio shortcode and also in the single portfolio view.
When using the portfolio shortcode the title and read more button will link to the portfolio post. Input a URL here if you want it to link somewhere else.
In addition to the read more button you can enter a URL here and a "Visit Site" button will display next to it when using the portfolio shortcode.
When using the portfolio shortcode each portfolio post will have an excerpt generated to display beneath the title. You can this field to display a custom excerpt.
Fullsize image for lightbox
By default your featured image will display in a lightbox when clicked on. You can place a URL to a different image here and it will display in the lightbox instead.
You can paste a youtube or vimeo URL here to embed a video with your portfolio post. The video will act like the featured image and display on the single portfolio view and when using the portfolio shortcode.
Link to post
By default your portfolio thumbnail will open in a lightbox when clicked on. If you check this then it will instead redirect the visitor to your portfolio post.
Disable read more
When you list your posts with the portfolio shortcode a "Read More" button will appear which when clicked on will redirect the visitor to the portfolio post. If you wish to disable this button then be sure to check this.
Disable fullsize image
When you view a portfolio post there will be a large image displayed (your featured image). If you wish to get rid of this then make sure to check this option.