To write a procedure essay you should concentrate on two things:
1. You have to use the imperative form, i.e. do this, do that,don't do this, etc.

Sometimes we were given flow charts with the -ing form and we had to remember to change this.
2. You must use linking words, e.g. first, secondly, then, next, after that, finally.

When you do a procedure essay you should include in it three paragraphs:

• the introduction must include 20 to 30 words

• the main paragraph and you must write from 90 to 100 words

• the conclusion and you have to write from 20 to 30 words