Hi, one option is to change the data retention time.
System Properties | Database | Data Retention. Set - Keep data for the last ? days in accordance with your requirements. You will be warned that data outside this period will no longer be available. Same for flows if you are collecting them.
The process described will delete all events outside the period chosen. The alternative setting is to keep all data allowed by the system, i.e. it will manage and use the space available. Are you getting some sort of error? If so, where? What are the symptoms?
You can simply select the timeframe, and events you want to delete. Drop down top left menu, and there is a delete option, it will delete the events from the ESM DB.