I can't seem to export my page, only the rectangle appears

Hey there, you need to select the content you want to export. If you want to export the entire page you need to select everything on the canvas. If your file has multiple pages, you’ll need to select and export content on each page separately. More information on exporting you can find here: https://help.figma.com/hc/en-us/articles/360040028114-Export-from-Figma.