Be careful they don't mean "attach brake module here".
You can probably find out by measuring the voltage across those two points. Best to use a Simpson or similar that actually draws current, but a DVM will work.
Make sure that you do NOT measure the bus voltage on them when VFD is not spinning the motor. You might get some leakage. be careful, there is probably 325V DC available there.
Then make sure that you DO get some voltage when you brake the lathe hard..... I.e. in circumstances that give an O/V trip.
If either condition is not satisfied, it's a non-starter, forget about it.
As for the resistor, figure the brake IGBT is good for maybe 1/3 to 1/2 what the main ones are good for. 3 HP is about 10A, 240V, so figure 3A or so, which suggests about 100 ohms minimum. Hopefully that is conservative.
You want a resistor that is 100 ohms, and can stand at least 4A pulse current (1600W pulse rating), and has a continuous power rating of probably 250W or so..... I happen to know those are available.
That will, with no further information, probably get you a functioning brake resistor.
You will need to mount it on a heatsink with some "thermal mass" which really means it's got fins and some weight to it, with a goodly block of material where the resistor mounts.
The brake pulses to keep the DC bus down, so you don't need a full-power rated resistor. You DO need a "pulse power rated" resistor.
I don't know what a stove element has for resistance. I expect less than 100 ohms. the only guy I know of who tried to use one also blew the brake IGBT in his drive, and was NOT happy.