CSS div's are not separating - html

Question

I have a problem aligning my div's side by side...
Here is an image how it should look:
This is the code for the main structure:
<div id="AttackDiv">
<div id="ImageDiv">
</div>
<div id="ContentDiv">
</div>
<div id="SkillDiv">
</div>
</div>
The "ImageDiv" is where the picutre is located. It takes up 120px.
The "ContentDiv" is where the text is inside and the "SkillDiv" is where the 3 other black boxes are inside.
This is my CSS:
#ImageDiv {
height: 100%;
width: 120px;
float: left;
background-color: white;
}
#ContentDiv {
height: 60%;
background-color: green;
}
#SkillDiv {
height: 40%;
background-color: blue;
}
Shows up this:
The problem is when I am trying to add those black boxes which you can see above in the image. Here is how it looks:
If I remove the white background color, you can see that somehow the Div's aren't aligning properly. They are kinda like running in each other.

Answer 1

Divs are block elements by default and, in the normal flow, they occupy 100% width of their container. So, naturally, div elements will stack vertically forming a column.
To make them align side-by-side consider these options:
apply float: left to all divs you want to display in a row
define the divs as display: inline-block
OR, for a very simple and efficient solution, just use flexbox:
Aligning Three Divs Horizontally Using Flexbox
Also, when working with floats, it helps to be familiar with clearfix methods:
What is a clearfix?
What methods of ‘clearfix’ can I use?
Clearing Floats: An Overview of Different clearfix Methods

Answer 2

Put the stuff on the right side into its own div container and then float it to the right.
If I understood you right, this should be it:
HTML
<div id="AttackDiv">
<div id="ImageDiv">left
</div>
<div id="RightSide">
<div id="ContentDiv">right1
</div>
<div id="SkillDiv">right2
</div>
</div>
</div>
CSS
#ImageDiv {
height: 100%;
width: 120px;
float: left;
background-color: white;
}
#ContentDiv {
height: 60%;
background-color: green;
}
#SkillDiv {
height: 40%;
background-color: blue;
}
#RightSide {
float: right;
width: 200px;
}
You can look at it here: https://jsfiddle.net/mxcqyjos/4/