Cubase is extremely complex and capable, and almost every users sets it up differently, and does things in different ways. As such, you really won't get anything from tutorials - the majority are by people who have little clue, and are promoting very weird workflows. For specific needs, you can find short tutorials - so if you are stuck with say, the compressors and dynamics tools, then these can be handy - but because many windows have different contents depending on what kit you have connected, and VSTi's installed, many tutorials just confuse.
Are you wanting to record real instruments and voices, or do you want to use soft synths? Recording style, as in press record, play and then stop, or pattern based? You say you play badly? As in a few mistakes, or just no ability or musicality? The treatment would be quite different - plus of course the genre of music. Somebody keen on rap and drum 'n' bass uses Cubase very differently from me who is into 'older' music - drums, bass, keys and guitars?
What are you having issues with?