Can you help me for making a multi room?

Issue:
Enter a description of your issue here, in full detail.
I want to make a kirby multi room but I can’t choose a preferred game. How can i add a preferred game??
In this massage, click on the plus icon in the game list but I can’t find any plus icon (I’m not good at english so my grammar will be bad sorry…)
System Information

  • Operating System: window 10
  • CPU:
  • GPU:
  • Citra Version (found in title bar): nightly
  • Game: kirby triple diluxe
  • Screenshot of Issue (include the full Citra window including titlebar):
    You must choose a Preferred Game to host a room. If you do not have any games in your game list yet, add a game folder by clicking on the plus icon in the game list

Diagnostic Log
Upload your log file as an attachment by dragging & dropping.

In order to save a copy of the log, follow this guide:
https://community.citra-emu.org/t/how-to-upload-the-log-file/296

In order for us to provide better support, we need to see the log generated by Citra. This guide will walk you through how you can obtain the log file: How to Upload the Log File.