Use the same grammar. The only thing you can "copy" is the grammar, you usually need to write your sentences in the same grammar. If you need to describe the difficulties you are having, then use the present continuous, e.g. The printer is not working. If you need to explain the reason for the extra meeting you had last week, use the past simple. If you need to talk about when you will be away, use will or if you explain more about your arrangements use the present continuous, e.g. I am flying to Shanghai on Monday 21st March.