1. Make sure you've installed Hex FX, as per the Installation guide
2. Open Maschine
   
   • If using a custom VST installation location, choose File > Preferences > Plug-ins > Locations > Add and select your installation location
3. Choose Master, Group, or Sound, then click the + icon to add an external plug-in, then choose VST3 > Serato > Serato Hex FX, and finally, double on the plug-in title to open Serato Hex FX:
   

If you’re using Hex FX for the first time, learn about activation or starting a trial.