SteamVR SDK Support is currently provided through the use of an integration package. If you require Steam device support (such as Valve Index or HTC Cosmos) you may use the OpenVR plugin along with XR Plugin Management, the SteamVR SDK, or the (preview) OpenXR Plugin.
If you want to give SteamVR a go, this integration package can get you started. It includes SteamVR bindings you can use to map SteamVR actions to raw inputs that the InputBridge can read.
Make sure no conflicting plugins are installed in the package manager - remove any OculusSDK and even OpenVR plugins before installing SteamVR.
Download and import the SteamVR SDK from the Asset store. Once imported, SteamVR will prompt you to generate keybindings - save and generate these.
VRIF includes some keybindings for a multitude of SteamVR devices. Extract the SteamVR package from /BNG Framework/Integrations/SteamVR and allow Steam to register these custom bindings.
(Optional) On the Player object add the "SteamVR_Activate Action Set on Load" component and drag in these new bindings.
Navigate to Window -> VRIF Settings and check the "SteamVR" integration checkbox. You can also manually do this by adding "STEAM_VR_SDK" (no quotes) to your Scripting Define Symbols : Edit -> Project Settings -> Other -> Scripting Define Symbols
You should now be good to go! Give the demo scene a run and try grabbing some of the demo objects.