Explaining a process is probably the easier among the task types in IELTS writing task 1. You just need to explain the steps, or the sequence involved in a flow chart. It is like explaining to a friend how something works like the winning Delaware elections flow chart below or how something is done like the steps in the production of oil.
Winning Delaware Elections Flow Chart by:
In this writing task 1 type, you need to use transition signals. Some of these are:
Initially, Firstly, First
Then, Next, Secondly, Second
Following this or that, Thirdly, Third, After this/that
Finally, Lastly, And the last one, In conclusion, To summ up.
Transition signals or linkers are used to indicate a shift of idea from one to another. They make the paragraphs coherent and therefore easy to follow and understand.
These signals give the reader an idea on whether the writer is moving from the present thought to the next without breaking the rules on coherence and unity.