I'm into bikes for a long time, but I still haven't got how to do maintenance of the bicycle myself so I only know how to change a tire and put some grease on the chain. I'd like to know the list of stuff I should check in my bike and how to fix/update it in different situation. I know, it's a really deep question that need a lot of typing, so I rather expect you share some links on reliable sources that fully cover the question.
Park tools publishes a book on bicycle repair and maintenance: Big Blue Book of Bicycle Repair.
Global Cycling Network has some maintenance videos on their YouTube channel
Performance Bicycles has maintenance videos on their YouTube channel.
For some good places to start, try: