how do I add html adsense banner code from Google?

[dreamer]

Trying to paste banner ad code from Google Adsense into html using Bluehost File manger. Succeeded with first attempt with ad showing up at bottom of my web page at www.dreamcatchersrus.com Tried to add a skyscraper 120 X 600 to take up the space on the right hand side of my web page but the code from Google just seemed to meld into the code I had previously pasted for the 728 X 90
Leaderboard and then neither banner showed up in the preview.

Can someone please help?
Thank you