Is it forbidden to ask for tutorial? or only bugs and problems? I didn't try to ask about tutorial before but in stackoverflow it is not allowed so i want to make sure
Tutorials are essentially a
"How to do X " type of question. These are acceptable, as long as they stay within the scope of the site ( about Ubuntu or its derivatives ) and not too broad. You did not specify which topic you want to ask, so it would be easier to determine whether or not your particular question will be acceptable.
On a side note, bugs and crash reports aren't very welcome, since they are not solvable by community members , but rather by the developers themselves, so they are off-topic here, sort of ; bug reports really should be directed to launchpad page of whatever package is in question.
IMHO asking for tutorials is asking for a lot of link and/or low quality answers. While asking for a lead my not be frowned upon as long you ask your questions like "how can i achieve -add your topic here-" they are not to broad to answer within the sites scope you should be fine. But expect your question to be marked as duplicate if it already exists with a given answer.