If you are reading this page then you didn't add a value for the RepoFolder parameter
Try one of these commands:
Out of Box Experience Start-OSDeployPad OOBE
OSDCloud Setup Start-OSDeployPad OSDCloudSetup
Edit-OSDCloud.winpe Start-OSDeployPad OSDCloudWinPE
OSDCloud Deployment Samples Start-OSDeployPad OSDCloudDeploy
OSDCloud Deployment Task Sequences Start-OSDeployPad OSDCloudTasks