Great Question!

Onboarding Panels are shown until dismissed and help you setup your Odoo database. 

For the Accounting dashboard, the Onboarding Panel looks like this:

If you dismiss an Onboarding Panel and realize you still want access to it:

Activate Developer Mode so you can access the Settings --> Technical --> User Interface --> Onboardings Menu.

Select the Onboarding Panel that you want to see again and select Toggle Visibility:

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