Note: You need Reason 9.5 or above to load VST plug-ins in Reason. For more information, please visit http://www.propellerheads.se/
For Mac:
1. After the installation, click on any space in Reason's Rack space to load BIAS FX 2:
Effects > PositiveGrid > BIAS FX 2 
2. Click it and you'll have a VST Rack for BIAS FX 2.
3. If you can't find BIAS FX 2 in Reason, please navigate to Preferences -> Advanced Settings and make sure the VST Plug-in folders have been set correctly.
Windows:
32bits - C:\Program Files (x86)\VstPlugins
64bits - C:\Program Files\VstPlugins
Mac:
Users/*username*/Library/Audio/Plug-ins/VST
4. Please refer to this article to know how to record in Reason.
*If you can't find the BIAS FX 2 plugin in the VST Plug-in folders, please make sure you've installed BIAS FX2 plug-in on your computer*