We have begun to add pages and content to this demo.As we mentioned on the outside of the site, saving and previewing are not possible from within the demo.
If you mouseover the Toolbar on your left, you will see notes that show the name of the Tool - and if available - the keyboard shortcut for the Tool.  Many of these Tools will pop another window that gives additional options.
In general, you will select a Tool - then click or click and drag on the 'artboard' to place the object.  To reposition an object, click and drag.  To resize, select the object and drag a corner selector.  Experiment, you'll get it.
Do not ignore the properties palette.  Each type of object has a set of applicable properties that can be set.  Select an object and play with the properties.  Even the 'white space' on this artboard has its own set of adjustable properties.
Click the Yellow File Folder to open additional pages.
The image below was drawn in a different part of the GYRE (Templates), which is used primarily for generating PDFs on line, but can also generate images, SVGs and HTML reports.  Click the image, look at the Properties and you'll see that it is assigned a link.
Do whatever you want - you can't 'break it' as nothing you do will be saved.
Click here and look to your right on the Properties palette - you will see that Visible is unchecked.  Now - go ahead and make it visible.  If Visible is unchecked - it cannot be seen in a browser.  You can use this feature to make notes to yourself - or as 'inner html' that can be loaded into a different text block by using a mouse event.  If you see one of these Notes on the other Demo pages, click it, make it Visible and read.  There will be additional info about a feature.
Notice that the text (above) has CSS attached, allowing you to 'override' the appearance in the GYRE.