Open your Course Tools and select the Quick Targets tool from the top menu. Use the dropdown menu associated with each hole to select which position each target is currently in, then scroll to the bottom and click SUBMIT. If some target positions are no longer available to play, then you can change those to Inactive for clarity. 

Once your new pin positions are approved, they will be viewable and playable in the UDisc app. The UDisc team manually reviews course and layout changes each day, so you can typically expect any changes to be reviewed within about 24 hours of submitting the edits.