You can find all the tutorials and guides for using the GOVUK Prototype kit here https://prototype-kit.service.gov.uk/docs/tutorials-and-guides
Commonly used guides
How to create pages from templates https://prototype-kit.service.gov.uk/docs/make-first-prototype/create-pages-from-templates
How to use components from the Design System https://prototype-kit.service.gov.uk/docs/make-first-prototype/use-components
How to Pass data from page to page https://prototype-kit.service.gov.uk/docs/pass-data
How to use layouts https://prototype-kit.service.gov.uk/docs/how-to-use-layouts
How to install and use plugins https://prototype-kit.service.gov.uk/docs/install-and-use-plugins
How to change the content within a page based on a user's answers https://prototype-kit.service.gov.uk/docs/conditional-content
How to show the user’s answers on the ‘Check answers’ page https://prototype-kit.service.gov.uk/docs/make-first-prototype/show-users-answers