Where to start time management ?! I’m a adherent of Step by step technique.

At the first stage, I recommend starting to use the concept INBOX (Untreated or e.g.).
You can start with a mailbox. I have two types of letters in my folder. “Unread” are letters that have just arrived, and which I have not even looked at. And “Read” are letters on which actions are required in the near future (prepare, read, attach, forward, etc.). All other letters are sent to the Archive folder. Once every two weeks, and sometimes a couple of times a week, I manage to clean my Inbox at zero. This is a great sense of accomplishment :)
I also have Evernote Inboxe. But more about that another time.