How I control the RPM of my motor from VESC with Arduino?

Hello guys...

I have a little issue and I hope somebody helps me.

I have a motor Gartt ML5010 300 KV and the controller VESC 4.12 and I want to adjust the RPM smoothly from a potentiometer or somehting like that. I use this configuration for a prototype. I know to do this with my laptop on Vesc Tool software but I don't want to use my laptop for this, I want to control externally. So, i try with servo tester used on testing the servo motors RC cars, but won't work. this stuff give me all the RPM instantaneous and can't control the RPM of my motor as i need! What posibility exist to control smooth the RPM or what kind of settings I need to make on Vesc Tool software? 

Thanks and excuse my poor english!