Coursepress content overview tinymce editor - sourcecode

Hi Guys ,

I am joining back here after a long gap , Hope that you all are fine and enjoying rain ,
I have a small question in coursepress pro plugin , When I creates a course , in 'Course Description' (2nd tab) , there is a wysiwyg editor (Course Description) , I want to add html code with some iframes in it , but here I could not see to edit sourcecode , Please can you guyz help me to edit sourcecode in this editor ?

Thanks