How do I know if an insurance claim I made was a buildings claim or a contents claim?

This depends on the item claimed for.

Anything permanently fixed to the building, such as walls, windows, a kitchen cupboard or bath for example, would have been covered under the buildings section of the policy.

Loose items, such as furniture, a television, jewellery or carpets, would have been covered under the contents section. If you're unsure, please don't hesitate to ask.