I've almost edited dashboard of wordpress but now i'm confused with sidebar I can't find page where appereance, posts, comments, settings etc etc. Can anyone know where i can find codes of that sidebar
What exactly do you mean by editing? I hope not modifying WP core files, which is considered bad practice and incompatible with updates?
Administration menus are considered to be some of the most nasty parts of code in WP and are hard to deal with. For some top level overview see Administration Menus in Codex, but for really deep customization there are no easy ways or guides (that I know of).