For tax year 2019 - 2020 - my acccounting period is 1st May 2018 to 30th April 2019 - how can I organise this

You can set this up on your tax profile, alison_darryl_ta.

To go to your Tax Profile page, select  Gear > Tax Profile.

You can toggle the Tax Year on top of the window to select the Tax year you would like to set up.

Furthermore, QuickBooks Self-Employed uses the Self-Assessment Summary.

Here's an article for guidance when you need to start your tax return preparation: How to use QuickBooks Self-Employed reports to fill in your tax return?

I'll be right here if you have other questions.