How to set up GST Clearing Account

I'm attempting to create my first BAS report. In Report Settings it asks me to choose my GST clearing account and the Help suggests creating a new liability account and choosing that. However, in the Accounts List there is already a Level 1 header category called Liabilities; under this, a level 2 header category called Current Liabilities; and, under that, a Level 3 header category called GST liabilities, and this account already has a current balance. I don't know where this comes from.  I tried selecting this account as my GST clearing account but it doesn't appear in the drop-down list.

I'm confused about what to do next. Should I ignore all the above and create a new liability category as suggested? What Level? Header or Detail?

Thanks in advance.