Question: I'm just starting a new app. Below is a basic mockup of what I am tasked to do. 
I'm new to using HTML5 for my semantic markup so I'd like some feedback/help. 

I'd like to understand how/where to use things like `<nav>` and `<section>`

```
<div id="container">
    <header>

    <div id="appInformation">
      <a href="#" alt="Home">
        <img src="">
      </a>

      <span>Selected AppName</span>
    </div>

    <div>
        <span id="time">TIME GOES HERE</span>
    </div>

    <div>
      <a href="#" alt="Additional Information">
        <img src=""><!-- This is will be the location of the the 'i'-->
      </a>
    </div>

    <div class="">
      <label>UserName</label>
    </div>  

    </header>
    <div id="main">
        <!-- main content for the selected app here -->
    </div>

    <footer>

        <div id="appVersion">
            VERSION # HERE
        </div>

        <nav>
            <ul>
                <li>
                    <a href="#">FAQ</a>
                </li>
            </ul>
        </nav>

        <div id="">
            <!-- Team logo here-->
        </div>

    </footer>

```

![enter image description here](https://i.stack.imgur.com/xw7cR.png)

Answer: 
* Avoid unacessary Div.
* Use the Time Tag instead of Div for Time Element.
* Avoid Label if you don't have anything to refer too, like an input.

 Selected AppName

```
    <time datetime="YYYY-MM-DD">TIME GOES HERE</time><!--  Don't need an id Time since you can target the Time tag -->

    <a href="#" alt="Additional Information">
        <img src=""><!-- This is will be the location of the the 'i'-->
    </a>

    <em>UserName</em> <!-- Don't use a label if you got nothing to refer too, like an input for example. -->
</header>
<div id="main">
    <!-- main content for the selected app here -->
</div>
<footer>
    <div id="appVersion">
        VERSION # HERE
    </div>
    <nav>
        <ul>
            <li>
                <a href="#">FAQ</a>
            </li>
        </ul>
    </nav>

    <a href="yourTeamUrl" id="">
        <!-- Team logo here-->
    </a>
</footer>

```
In addition to @Simon Arnold's fine answer, I might also suggest that the `<nav>` usage is incorrect. A single link in a footer can hardly be construed as a "major navigation block". See the first note in green text at <http://dev.w3.org/html5/spec/sections.html#the-nav-element>