This is the page I told you about. Consider this your 'Squarespace playground'. You will notice as you hover around certain drop-shaped buttons and black lines; the lines determine the places you can insert objects and the button gives you a broad choice of widgets you can insert. Another method of adding blocks, is by clicking on the plus icon on the top-right corner. You'll open a grid of blocks that you can drag and drop. Have fun and let me know how if you encounter problems or have questions!
Note: Make sure you only edit the 'Page Content', otherwise you will change site-wide elements such as the 'Footer', 'Navigation' and 'Site Title'.