Create data to test interface

Apologies, Im an absolute noob and after struggling around am hoping for a point in the right direction. Ive been asked to create a data file to test an API from an existing dataset (I have created an excel file but can turn it into any format). My boss tells me that this can be done easily in the swagger editor but not how....  I have the yaml file and the data, but cant figure out how to use the swagger editor to create the dataset according to the schemas detailed in the yaml file. Im sure its obvious, just not to me! Appreciate any help on offer 🙂