In the Blank Document templates in the ARPHA Writing Tool you do not have any ready sections apart from your metadata. 

Step 1. Click the Add section tab to open a section for first use.

Set the title for your section, add and edit its content, and manage subsections in the pop-up window that will appear. 

Now, the section becomes visible, so that you can continue working on it straight in the manuscript by simply clicking within the text. A toolbar will appear either at the top or at the bottom of the section. 

Step 2. When you hover over the extra sections you have created, you can see a set of buttons. Use  to add and edit the text;  to delete the section;  to move it up and down the order;  to add subsections, which you can then edit in the same way.