Custom Sandbox Configuration Issue

Question

I am attempting to make a custom WSB Windows sandbox file and am having issues. I want to make it so every time I open it, I can use it for malware analysis. I want it to come with Malwarebytes, a network connection, the ProtectedClient Enabled, Clipboard, and anything unnecessary to be disabled. I have attempted to make the file attached below, but when opening it, it will tell me the file is not found on the sandbox and close. Sandbox opens fine when using it without any configurations. I am not sure on how to preinstall specific software and need some help on this. But more importantly, I want to to run the way I have it labeled below. I have also attached the error that I get. I am not sure what I am doing wrong here and followed the instructions on the O365 Windows Sandbox Config. documentation.