Once you have created your make, you need to "share it" and make it publicly visible, If you are having trouble see the google help page here
Having made the map public, you now want to get the code to embed the map on your site.
the code that google gives you is something like :
<iframe src="https://www.google.com/maps/d/embed?mid=zQwbgagDTQg4.kVtlQk1vnt48" width="640" height="480"></iframe>
to embed it on your Itseeze site, all you need to do is strip out the unnneccesary coding (as Itseeze do the hard stuff for you) to the following
then select the iframe component (its in the "structure" tab within the editor, you have to scroll down as it is not immediately obvious that it is there) set a few parameters (the height of the frame) and paste in the stripped out iframe code .. and voila ... your map appears on your website, just how you want it !