You will need to build and deploy the Mod to your Oculus Quest to test it.
The good news is the example project (GladiusModPak) already comes with 3 scripts that make this process very easy.
Select ClearPlugin.bat and right click on it. Then select Edit.
Modify the PLUGINNAME variable, and replace InfinityArena with your plugin name. Then save the file and close it.
Now edit CompilePlugin.bat and modify the PLUGINNAME variable like in ClearPlugin.bat, and also modify the UE4 installation folder, which by default installs to "C:\Program Files\Epic Games\UE_4.25\" with the Quotation marks.
Repeat the process with CopyPlugin.bat. Edit the files and replace the variable PLUGINNAME with your plugin name.
If this is the first time you connect it after enabling the developer mode you will need to accept the Debug permissions request pop up inside the headset.