How to Add Picture to Front Page

This may sound silly, and I should probably know this but I have been banging my head against the desk seeking an answer.

On Small Business Free Edition – how do you place a picture in the large gray slider box on the static home page?

A detailed walk-through would be most appreciated.

I’ve looked at the code in editor and for the life of me I can’t seem to figure it out.

The page hasn’t gone live yet, so right now it’s just a temp domain at https://www.temp.smart4life.org.

Thanks!!!