1. configure online validation in zmodeler, so it downloads and validates your license automatically at startup;
2. ensure zmodeler folder is not read-only; add it into exclude list of your antivirus. License installation creates a file "Codelib.dynamic" in "Shared" folder of ZModeler - once license is installed, this file should appear.
3. Restart ZModeler, open License window; you should see your key installed there when you open window; an online check should be passing and should end with the label like on your first screenshot ("revalidate in 6 days"). You can close license window and you should be able to open/import files from this moment.
Note, #3 is essential for short-term licenses; installing a long-term license (6-month and more) will allow ZModeler to run offline during validation period.