StereoKit:

• StereoKit Overview
• Getting Started Guide 
• GitHub 
• Video series 
• Sample projects 
• Ask a question 
• Submit a Bug

Tools: 

• Visual Studio
• OpenXR Overview 
• If you don't have access to an HMD, you can use: 
  • StereoKit simulation fallback
  • HoloLens 2 Emulator
  • Windows Mixed Reality Simulator 

Other: 

• Joining an event in AltspaceVR 
  • Getting started guide 
• Sign up for Microsoft's Mixed Reality Developer Program