To starting using X DupFile, select Action/Scan Disk... in the menu or simply click the scan button located in the toolbar. And then you will be asked to select disks or directories for scan,

Next step, you can select checkbox for compare files while scan finished or select nothing the scan wizard will close by yourself.

Then wait a moment, scan finished, and you will find the scan results have grouped by file size. Select the groups of you interested and select Action/Compare Files... in the menu or simply click the Compare button located in the toolbar, start the compare process.

Minutes later, you can find duplicate files at Result View, then you can check the files you want to delete and select Action/Delete... in then menu or simply click the Delete button located in the toolbar.