I have a Delta 36-650 table saw set up for 240 v use. The motor is already configured for 240 use. Not sure how to hook it up to the breaker panel.
New breaker panel and new location.
Ah, the famous Delta Contractor's saw. I used one of those for decades before I got my SawStop cabinet saw.
That saw is designed to be cord and plug connected. Read the manual. It's designed to have a 15A 240 (6-15) Plug on it when you are using the 240V mode. I'd put in a 20A 240 Receptacle (6-20) which will accept the 6-15 plug but leaves your options open. I'd not put anything else on that circuit (at least nothing you'd tend to run at the same time as the saw).
This diagram shows the shapes for each receptacle type.
Assuming you have a standard panel and no need to use conduit to protect the wire:
Just run 12/3 NM wire from the 6-20 or 6-15 receptacle to a double breaker in the panel. Connect black and red wires to the breaker, and white and ground to the bus in the box. Follow the instructions that come with the receptacle to make sure its wired correctly. Make sure you shut off the main breaker when working in the box.
"and white and ground to the bus"
Why would you run a neutral to a 240 volt receptacle?
As I stated, this saw only requires a 6-15 (2 hots and a ground) which is what is shown in the manual. There's no need for a neutral (nor any place to connect it on that receptacle). In some cases I might run a neutral to the box just in case I needed to hook up a four wire circuit in the future, but here I wouldn't. I have four 240V receptacles in my shop running a larger table saw than this, a dust collector, an air compressor, and a jointer/planer. None of them needs a neutral. 12/2 would be fine here.
There's no place to connect that white wire not he 6-20 receptacle.
It is not the case that you connect the grounded (white) and the ground (bare/green) to the same bus. This only can happen at the service disconnect. The suggestion of a new panel indicates this MIGHT not be the service disconnect but rather a sub panel.
Further, you can not put a single 15A receptacle on a 20A breaker.
There's neither a requirement to shut off the main breaker (if there even is one) nor does shutting off the main breaker reenergize everything in the panel. If you don't know what you need to do to work safely in the panel, you should have an electrician come in to do the work.
If the receptacle,contains two outlets, you can use it on a 20 amp circuit. If it's a single and ther no other outlets on he circuit then you must use a 20 amp receptacle.
Putting the outlet on a nearby wall switch (double pole to disconnect both legs) makes it convenient to kill power to the saw when changing blades and such. While it would be hard to do I could imagine leaning on the switch on my PM66 and turning it on inadvertently. Rather not do that while handling the blade.
That's why the cord conveniently comes out of the wall (it can serve as a disconnect), but an appropriately rated switch will work as well.
My cord comes conveniently out underneath the saw, where I don't trip over it while working. However I have to get on my hands and knees to unplug it, making it a less-likely-to-be-used disconnect.