How to edit Content Editor Web Part with HTML Text editor in SharePoint 2010

Adding Content Editor Web Part in SharePoint 2010
Editing Tools | Insert | Web Part

Under categories go to media and content to add SharePoint 2010 content Editor web part
Categories | Media and Content |  Content Editor

Click Add to insert Content Editor Web Part in SharePoint 2010 page

Your web part will say “ Edit this web part to add content to your page”  Click on Content Editor Menu and go to Edit Web Part 

As soon as you click on Edit Web Part, the message in Content Editor web part changes to “ Click here to add content” 
Now you can click on HTML under Format Text and click on Edit HTML Source

Editing HTML Source in SharePoint 2010 content Editor Web Part

In HTML Source Editor you can input your HTML source.  This is how you edit Content Editor Web Part to add html source in SharePoint 2010