Log in to your website
Visit https://www.squarespace.com/login to log in.
To add a single image, follow the instructions here. To add a gallery with multiple images, visit this page to get instructions and see your options. To see an explanation of thumbnail images and how to add or change them, go to this page and click 'WATCH VIDEO' near the top.
To start editing text, go to the section or page you want to edit, then click Edit as shown here. Be sure to save your changes.
Add a new blog post
Squarespace Website Guide [PDF]
A short, 5-page guide put out by Squarespace. It is similar to this page but adds links to help for things you might want to do beyond the very basics covered here. Get the guide here.
Get help with something else on your website
Tech support from Squarespace is included in your plan. Probably anything you might want to do with your website is covered in their Help section, and that is the quickest way to get the job done. If you can't find what you need in the Help section, you can contact Customer Care for assistance.
Note: Avoid the "Community Answers" section you'll see as an option near the bottom of the Help section start page. This is a user forum and has more wrong answers than right ones.
If you need help with a redesign or something more complicated than you're comfortable handling, I can often assist with these smaller projects. Prices start at $150 and vary according to complexity. To inquire about availability, please provide details via e-mail or my website contact page.