My hosting service installed DNN for me and I'm embarrassed to report that I've done something stupid twice.  What am I doing wrong or failing to do?

Here's what I've done twice following the fresh install by my host:

I typed my URL into my browser (IE7).  Up came my DNN-based home page came up. I logged in as administrator and changed my password.  I may have added to my profile. I did not do anything with HOST.  I did not click REGISTER.
Then, I spent a great deal of time becoming familiar with DNN features, the DNN "marketplace" of related products, etc.

Then, I used the built-in Site Wizard which primarily dealt with skins.
I then uploaded my own Logo to replace DNN's. I poked around some more in Control Panel but really didn't do anything there except learn.
When I was through, I simply logged out by clicking the Logout button.   I did not see anything resembling a "SAVE MY SITE" button or option.  I did not "close" it by clicking the X box at the top right.
That's all I did.  Now, when I type my URL the DNN-based home page comes up, but I cannot login. 

Do you know what I'm doing wrong or failing to do?