Config menu then Motor Tuning, change the velocity to a lower value then click Save Axis Settings.
Is your machine a conventional two axis lathe? If it is then you will need to configure you axes correctly or you will run into all sorts of issues with your G Code and toolpath etc.
On a two axis lathe the axis that moves towards and away from the chuck is the Z. The axis that moves to centre line of chuck and away from centre line is the X.
X positive is the axis moving further out from centre
Z Positive is axis moving further away from the chuck, ie towards the tailstock.
Hood