You can add widgets and other codes directly into the content section of a page
Go to the page where you would like your code/widget added
Click on the Content Tab
Click into your content section (or if this is a new page, click add new row with (1) column
In the content toolbar, click the 'source' button (left-hand side)
This shows you what you currently have in the content section, in an HTML script.
Copy and paste your widget code underneath your content, in a new line
Now that you've added your widget code, click 'OK'
Depending on what code you have added, you may see the content box is populated, or it may appear empty. If you've added an iFrame, you should see a red box.
Remember to click 'save' so that the changes go live, and always check the front end to see how it looks