How do I set an ASP.NET Label text from code behind on page load?

I can't seem to find an answer out there for this. Here's the scenario: I have an ASP.NET project using C#. I'm loading data (Username, email, etc...) from a sqlite database with C# (using ADO). I'll be loading the data into static Global variables in a class file in my App_Data folder. I need to be able to insert the username into an ASP.NET Label on a page during load.

In PHP, I would just do it like this:

<?php
function GetUserName() {
//code which retrieves username from db.
return username;
}
?>
<p>Here is the username: <?php echo GetUserName(); ?></p>

Can anyone explain how this is done? I'm new to ASP.NET.

Here's an update for some more detail. I tried what you guys have suggested. My page load function is in a file called RankPage.aspx.cs and the table below it is in RankPage.aspx. The idea is to list a bunch of users that I've retrieved from the database. I threw in 'myLabel' just to test it. Right now, without declaring 'myLabel' in my code behind, it errors that 'myLabel' does not exist in the current context. If I declare 'myLabel' using the FindControl() function, I get a runtime exception that 'myLabel' isn't set to an instance of an object.

Here's the code:

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        Label myLabel = this.FindControl("myLabel") as Label;
        myLabel.Text = "my text";
    }
}

<table>
    <tbody>
        <tr>
            <th>Name</th>
            <th>Score</th>
        </tr>

        <tr>
            <td>name</td>
            <td>Score</td>
        </tr>

        <!-- Current User -->
        <tr>
            <td><asp:Label id="currentUserName" runat="server"></asp:Label></td>
            <td><asp:Label id="currentUserScore" runat="server"></asp