Right-click the backup file you want to remove and then select Delete.
Then, you need to find the backups you want to delete (you can select the target ones according to their created dates). Open the subfolder and you can see your backup files are named as the date they were created.You need to expand that folder and then find the subfolder for your Mac that has been backed up. Then, you can see a folder that is named backupdb.Then, you need to click that backup drive to continue. You can see your external backup drive under Devices from the left list.Connect the external backup hard drive to your computer.You can follow this step-by-step guide to remove old Time Machine backups: You can also use Finder to delete Time Machine backups. Method 2: Delete Time Machine Backups Using Finder
HOW TO DELETE FROM TIME MACHINE ON MAC PASSWORD