The software you are looking for is Candle (formerly GRBLControl ), an open-source GRBL controller application with a G-Code visualizer. Version 1.1.7 is a widely used legacy version for CNC machines like the Genmitsu 3018.
Candle is a free, open-source software designed to control CNC machines running on GRBL firmware. Version 1.1.7 is the "Gold Standard" release, featuring a streamlined interface, essential probing tools, and high compatibility with GRBL 1.1 builds. It is the recommended software for beginners and intermediate users operating desktop CNCs like the Genmitsu 3018, Sainsmart, and generic GRBL-based machines. candle 1.1.7 download
Once the CNC is connected via USB, you must select the correct and set the (usually 115200 for GRBL 1.1) within the software settings. The software you are looking for is Candle