Need Assistance Running Multiple Clients

I just got another copy of the game, and wanted to use it to help with testing things out (The current test release for example) and maybe gathering a little more.

Would someone be able to help me in setting things up to be able to run both of my clients side by side? I currently have “sandboxie”, something someone else I saw during the last Gleambow event was using. I have my other Steam account running there, but any attempt to run Boundless in it fails silently.

Btw, I realize this is category is more for support with the game itself. If there’s a better place for this, please feel free to move this!