How to unhide fields that have been hidden on load, when i choose an item from a visible dropdown? Then unhide another dropfield or fields on select from this now visible dropdown and so on???

How to unhide fields that have been hidden on load, when i choose an item from a visible dropdown? Then unhide another dropfield or fields on select from this now visible dropdown and so on???

Hide many fields with hide on load. Now when i make a selection on "Product types" want to unhide some hidden field / fields. Getting errors.. not sure about the script needed