All new items are added to the top of the left column. You can then drag them to anywhere you want with the edit bar at the top of the item. Just put your cursor over the edit bar (NOT on the word "edit" or trashcan icon) and the cursor will change to a hand. Click AND hold the mouse button down. While you're holding, drag the item anywhere on the page. You'll notice a red dotted outline of a box. This represents your item. When that red outline is where you want it to be, just let go. This might take a bit of practice, but soon you'll be a pro.
You can also use the edit bar to edit content or delete the item. To edit, just click on the word "edit." If your item is a graphic, you'll see the graphics window. If it's an article, you'll see the articles window. You can then make any changes you want or click "Cancel" to leave it the way it was.
To delete an item, click on the trashcan on the edit bar. A window will appear that asks if you really want to delete the item. Say "OK" and it's gone. Click "Cancel" if you've changed your mind.