1. You will need to purchase a drive box/stepper motors kit. Here are a few kits that I would recommend. Click on the links below.
MX-P423-400 By AMT
4-DM542T-23HS45 By StepperOnline
2. You will need to purchase or make a router/spindle mount. I highly recommend the router/spindle mounts sold by www.cncrouterparts.com
3. You will need to purchase a router or spindle for your machine. There are many to choose from and you may already have a router in your shop.
4. You will need to purchase some type of Controller software such as Mach3, Mach4, or UCCNC.
5. You will need to purchase some type of program/design software (CAD/CAM).
What else do you need to complete your machine?