Get onto the main page where you click on the icon to edit the form. The icon to the right of that says Edit CSS. Click on this.
About 50 lines down there will be a heading that says:
/**** Logo Section *****/
Just below that is where you want to make the change:
#main_body h1
{
background-color:#ffcc33;
margin:0;
min-height:0;
padding:0;
text-decoration:none;
text-indent:-8000px;
background-image: url('../../../images/TinyLogo.gif');
background-repeat: no-repeat;
change background-image: url('../../../images/TinyLogo.gif');
to whatever the location is for your logo. For example
background-image: url('http://www.yourdomain.com/images/header.jpg');
That should solve your problem.
As for your observation that the application does not appear to be user friendly...I have 28 forms that I currently have designed on this application. It does take some trial and error, but I eventually get things to work. This forum is invaluable in getting questions answered.
If I had to pay someone to design each of these forms, it probably would have cost me over $5,000. The $40.00 I paid for Machforms is the best investment I ever made. I can hardly wait for their new version.