1. It’s very easy. Please edit the portfolio entry, click the “Add Media” button above the editor, then choose “uploaded to this page” in the dropdown. Now WordPress will show you only the uploaded images to this portfolio entry. Sort now the images with your mouse. After this, close the pop up window and save the post, that’s all.
2. Doesnt appear the icon with the link?
3. Please go to WordPress admin -> Appearance -> Theme Options -> Body -> Smooth Scroll and uncheck the checkbox.
By the way: great website, I like it!