Once you have a published site, you can make changes to your galleries, pages and projects and then apply those changes to the live site by clicking "Update Live Site" on your Remote.
To make changes to your projects after you have published your work, just hover over the projects, and look for the pencil icon. If you click on it, a drop down with four options will fall.
You will have the options to customize your layout options, edit your project cover image, edit the information for your project or edit the project content.
From the edit project content page, you can make changes to your project via the project editor and then when you are ready, you can click "Save Project." When you click back to your homepage, you can hit "Update Live Site" at the bottom of the page and your changes will push to your live site.