Tuongvan

“By the beginning/end  of next year, the company will organize a workshop on human resources management.  This is a little problematical, since "by" sort of implies completion, and the verb "to organize" doesn't imply completion.  I'd suggest other verb forms.  " . . . .  the company will have organized . . . . ";  " . . . will be organizing . . . ";     " . . . will begin to organize / organizing . . . "  (This very last example may be argumantative.  Though it's often used, it may be incorrect.  "Will have begun" may be necessary.)

At the beginning/end  of next year, the company will organize a workshop on human resources management.  This means that at the specified point in time (beginning or ending of the year) the process of organizing the workshop will commence.

In the beginning/end of of next year, the company will organize a workshop on human resources management.  In the beginning/end would not be used in this way.  It would rather be used to describe something in the past, or a prediction for the future.  In the beginning it seemed quite innocent, but his intentions gradually became clear.   Although it was terrifying, in the end we were glad it had happened.   In the beginning, it will sound like a train approaching in the distance.   In the end you'll be glad you put money aside for your vacation.”