adding a HTML module into page

Hello, If you go to my website HEDClothing.com, i have a "Athletes" tab to list out sponsored athletes, i want to add a Html module into it.

i have tried everything and read multiple "tutorials" and it does not work.

i am on the latest version.

if anyone could help me out it would be appreciated, you can email me at Info@NZembroidery.com it is easier to get in contact with me