Dynamic shares offer many different options to configure how you want to share data from your instance. These options include:
Share updates since then
This option on the Simple view (and found under the Runtime Settings tab of the Standard view), this option will bulk share only records that meet any conditions you specify in the bulk share and have been updated since the last time the bulk share is run. This option is useful if you have this bulk share as part of a scheduled bulk share and only want to share records updated since the last time the bulk share was run.
On the first run of the bulk share, it will share all records based on the conditions you set.
Enable debug logging
Found under the Advanced tab of the Standard view, this option enables debug logging that can be found under Troubleshooting for any execution of this dynamic share to help you troubleshoot issues with your sharing.