Homebuilt,
How what are you having trouble with? The Steps Per Unit or the Velocity and Accel?
For Steps Per Unit, I found a couple of resources that are worth looking at.
The first is Artsoft's YouTube Channel: Steps Per Unit Calculator Wizard.
https://www.youtube.com/watch?v=d-xCWDR0UvgThe next resource I found gives you a formula for finding the correct SPU. (You can stop reading once you get to the formula)
https://planet-cnc.com/how-to-setup-cnc/For Velocity and Accel; I'm sure someone else will have a better explanation than what I do, but this is how we do it.... I like the old trial and error approach. First, calibrate your axis, otherwise this will be pointless because it will change with calibration. Once I know that all my axis are calibrated correctly, I decide what the Max Rapid Rate for my machine should be or where I want it; this will depend on how strong your motors are for your table, I retrofit lathes and VMCs mostly so I use good size servos so I can get good speed out of my machine. Your Velocity is the max units per minute the machine can move; for example, the mill I'm working on is currently set to 450 units (inches) per minute. If you are unsure how fast to set the velocity, start high and keep adjusting your velocity down until the motors don't stall while jogging, then go 3/4 of that speed and you should be good to go.
As for the acceleration, I usually go with 10% of my velocity and 95% of the time it works great. With servos and hybrid steppers it could be a little less because they have the feedback from the encoder; but again, this is trial and error, if you machine table is a heavy, has small motors, or is a gantry type machine, it will likely have to have a higher acceleration to not stall your motors.
Like I said, someone may have a more scientific or mathematical approach than what I do; but this has always worked for us. Maybe someone else will share their experience, I'd love to hear it as well.