In that left hand side box, you'll notice a green + icon in the top right:

Clicking on it will enable you to create a new post!

The new post page will enable you to place your title at the top, then create your content in markdown along the left and generate a preview on the right (more about markdown language and shortcuts soon).

It takes a little getting used to, but to add an image for example, you decide where in the markdown on the left you'd like to add it, add the markdown code, then an image upload area appears on the right hand side (click on it to upload an image or drag it right in):

Inside the markdown, you'll notice that the image code will change once you've uploaded the image (with it's location on the server) and you'll be able to add in your "alt" tags between the square brackets - more on this in the SEO section.

If you click on the question mark symbol along the top right of this same section, you'll pull up a list of the most popular markdown language shortcuts.

Other features on the new post page are found in the bottom left and right hand corners.

Along the left you can add tags to your posts (you should pick broad categories and stick with those as you write. Things like: Mobile, Tech, Startups etc.)

Along the right hand side, there are two pop-up menus:

The first is for additional settings, at the moment this includes setting the post URL and publication date (the format is DD, MMM, YYYY).

The second is the "Save/Publish" option: