How to make a section stick/freeze on page

Is it possible to have a section on a page stick/freeze at the top? 

Yes, but how you do it depends on the version of Squarespace you are using and sometimes the template. 

There are lots of resources on the forum and discoverable with a quick Google:

What is your website URL?

@Ziggy 

https://grape-piccolo-zmts.squarespace.com/config/pages

Password 123123

I would like the top section of my portfolio page to be a second nav menu where it would stick on top as I scroll through my portfolio. Additionally, I would like to be able to click on "graduate," and it drops straight to that section (not a new page)

I don't see a portfolio page or a link for Graduate, can you share that link specifically?

It does sound like you want an anchor link for Graduate, see this:
https://squarefortytwo.com/squarespace-guides/adding-anchor-links-on-squarespace

This may help with what you're describing for a sticky second nav:
https://www.beatrizcaraballo.com/blog/sticky-content-navigation-squarespace