The dip switches for the DM542 are as follows:
Switches 1, 2, and 3 relate to the amp setting for the motor connected to the driver. Take a look at the datasheet for the motor that you have. If you are connecting the 425 oz-in NEMA 24 motor, the Amp setting should be around 2.8, so the dip switch setting is 1-on, 2-on, and 3-off. If you are using a NEMA34 motor from buildyourcnc.com, set the amp rating to the highest at 1-off, 2-off, and 3-off.
Switch 4 is the setting for half or full current when the motor is at idle. You can set this to either full or half, unless you are using a rack and pinion and the axis is experiencing a load, like gravity. In that case, make sure switch 4 is on for full current.
Switches 5 to 8 relate to the number of micro steps for each step. A stepper motor with a 1.8-degree step will have 200 steps per rotation. If you wish to increase the number of steps per rotation, you can set these switches so that you can have more granularity. This will depend on the mechanical configuration of the axis you are setting. For instance, if you are using a lead screw that has a lead of 1/2" travel per turn, you will want to set the axis to at least 1/4, or 800 steps per rotation. If your mechanical configuration is rack and pinion, or roller chain, you may want a higher micro stepping to achieve greater than 1000/inch resolution on that axis. For instance, if the axis has a drive sprocket with a roller chain that has 14 teeth and the tooth pitch is 1/4", use a 1/16 microstepping setting or 3200 steps per rotation.