If WinUnisoft is out of reach, there are excellent free/open-source CNC simulators that can help you learn:

An excellent, fully open-source 3D CNC simulator that is perfect for visualizing G-code cutting paths. Conclusion: Protect Your Data

Developed by Alecop, WinUnisoft is a leading tool for teaching CNC (Computer Numerical Control) machining in a risk-free virtual environment. It allows students and professionals to edit, simulate, and verify G-code programs for both lathes and milling machines. Core Modules

Ensure you have updated antivirus software running before downloading any software.

Seeking unauthorized "full gratis" versions poses significant risks: