Thought all you three did not answered directly to my problem, but you made me realize that I have to restart installation using a guide and not my experience (from the close but so different “Windows Planet”) using an approach not working well here. Thank you all for these answers. I will use my time to exercise the information you gave me and understand better the new environment.
I found the current problem I faced and it came from the 1st installation partitions which I thought I deleted all but left root or boot so it asked me for the 1st user login info. Even partitioning method is different from windows. So, I repeat for 3rd time but more carefully the installation and now I login normally. Looks like Linux let me with freedom I did not used to, so I got offered options I used to see them as unorthodox before, options not common in windows.
Learning from scratch here. Done before, patience is my best friend.
I really appreciate your help a lot and I need it.