Hi Justine! Squarespace is great for blogging! Follow the video I sent you. Feel free to open this post and give it an edit to see how the interface works. Once you are writing/editing a post, you will see tons of extra options.
SquareSpace provides a ton of fantastic resources, including quick tutorial videos about the UI. If you get stuck, give them a whirl. It's pretty simple once you get the hang of it! Of course, reach out to me if you get stuck! I can help, though am still learning my way around squarespace =D