Using H5P content is just like adding any other material. Either use the drag and drop upload option highlighted at the bottom, or click on the Add Material button.

If you use the Add Material button, make sure you select the file using the Single File upload option.

Once the file has been uploaded, it may take several minutes for the platform to unzip the package and display it properly. Once it's been unzipped, you'll be able to preview it and use it in any of your courses.