The screenshot you shared of the error doesn't actually contain any error information, it just shows the usage output from UnrealBuildTool.

Since I can't see the log of what actually failed, and since you said you're relatively new to UE, I will recommend ensuring that you have installed and configured Visual Studio correctly. There are a number of additional components that you must explicitly configure in order for UBT to function.

See this official Epic doc on how to install and configure Visual Studio for UE dev.

After you ensure your VS installation is correct, try to Generate Project Files again. If that doesn't work, please share the new screenshot of the error (try to scroll up above the usage information to see the actual error).

Ideally instead of a screenshot, copy+paste the log if you can.