How would you make two <div>s overlap?

Just use negative margins, in the second div say:

<div style="margin-top: -25px;">

And make sure to set the z-index property to get the layering you want.

I might approach it like so (CSS and HTML):

html,
body {
  margin: 0px;
}
#logo {
  position: absolute; /* Reposition logo from the natural layout */
  left: 75px;
  top: 0px;
  width: 300px;
  height: 200px;
  z-index: 2;
}
#content {
  margin-top: 100px; /* Provide buffer for logo */
}
#links {
  height: 75px;
  margin-left: 400px; /* Flush links (with a 25px "padding") right of logo */
}

<div id="logo">
  <img src="https://via.placeholder.com/200x100" />
</div>
<div id="content">
  
  <div id="links">dssdfsdfsdfsdf</div>
</div>

With absolute or relative positioning, you can do all sorts of overlapping. You've probably want the logo to be styled as such:

div#logo {
  position: absolute;
  left: 100px; // or whatever
}

Note: absolute position has its eccentricities. You'll probably have to experiment a little, but it shouldn't be too hard to do what you want.