im on mac and it keeps on saying that this file is damaged when i want to open 'GDSIM'
Right, I am aware of this.
Unfortunately, because I am not an Apple developer, I cannot properly sign the app. I also do not have Mac hardware for testing or proper support. For GDSim, you may use the following instructions.
Because of this, I have decided not to export to MacOS in the future. Sorry!
https://www.howtogeek.com/803598/app-is-damaged-and-cant-be-opened/