Hi Seri, welcome to he site and well down on taking this important step to recognise and sort out your gambling problem.
As for the journal- it is your journal . Write what you feel Kiel writing about . One day you might like to write about how you stayed gamble free, another you might like to write about how your addiction began.
There is no right way to write a journal.. There is no wrong way either
Write what comes into your head at the time ..
But we would all love to hear your story when you are ready to share it!