The user/owner manuals that come\cae with bicycles was\is pretty generic. And mostly useless.
Google is you friend, just search for "How do i adjust " component name.
Most bike adjustment, repair, service isn't terrible difficult. Well within the reach of average mechanical skills. A good set of allen wrenches is a good place to start for tools, along with a screwdriver, and a willingness to try to do the work yourself.