First of all, a big thank you to AMDbuilder who helped me through the first hurdle. For those who encounter the same problem, the install interface asks for "database login name" but what that wants is what you probably created in cPanel as "database USER name." It is the bi_word made of the domain account name connected by an underscore to the word you chose as your db user name (domain_user).
Unfortunately, the install screen invites you to validate what you entered. In my case, it passed and gave me the green text approval message even though I had only entered the second half of the user name.
Now I must move on to the next frustration.
Moving along in installa tion screens, I came to:
Pre-install validation
Setup has carried out a number of checks to see if everything’s ready to start the setup.
Checking PHP version: OK!
Checking if Register_Globals is off: OK!
Checking if sessions are properly configured: OK!
Checking if assets/cache directory exists: OK! (It didn’t but I created it. I’m wondering why it was left out of the zip I downloaded.)
Checking if assets/cache directory is writable: OK! (and I modded it to 777 - why do the instructions assume that I know that number. What wopuld it take to offer that simple advice to others?)
Checking if assets/cache/siteCache.idx.php file is writable: FAILED! (Well of course it failed. It is not writable because my upload did not include the file. Should I create one and upload it?)
Checking if assets/cache/sitePublishing.idx.php file is writable: FAILED! (same story. No file in the upload. I am beginning to think I have a defective upload here? Again, am I expected to create an empty file of that name and upload it? Would that work? ).
At this point I need to pause while I request help with those questions. Anyone, please?