Although you don’t need a lot of technical chops to get it done, it does require some practice. For the most part, much of this stuff can be managed if you’re comfortable dragging and dropping boxes. It’s important to note if you’re in a multi-user trial, only the first user, who has an admin profile, can access this ‘behind the scenes’ area. VIP status!
Watch this video that walks you through how you can add/remove/reorder fields.
If you want to edit the tabs you see in the horizontal navigation bar, click on the pencil icon on the far right. This will allow you to re-order the tabs, so that ones you need most are moved to the top (when editing), and will display furthest to the left when you're done making changes.
If you want to remove a tab completely, as an admin you can do so.