Update 
Update 

Added link to design guidances on MS Dev pages. 
Renamed Conceptual to How-to to align with the actual naming on the page
vladkol/MixedRealityToolkit-Unity,killerantz/HoloToolkit-Unity,DDReaper/MixedRealityToolkit-Unity,killerantz/HoloToolkit-Unity,killerantz/HoloToolkit-Unity,vladkol/MixedRealityToolkit-Unity,vladkol/MixedRealityToolkit-Unity,killerantz/HoloToolkit-Unity