USB shield – usb host shield
if you will not use External Power please be sure this jumpers are soldered as below :

so after soldering it will be like this image

Prototype Shield for Arduino MEGA
1 × 35 SAR
Resistor 82 ohm_1/4W
1 × 1 SAR
CNC Shield Expansion Board+4x A4988 Stepper Motor Driver
1 × 172 SAR Subtotal: 208 SAR
Prototype Shield for Arduino MEGA
1 × 35 SAR
Resistor 82 ohm_1/4W
1 × 1 SAR
CNC Shield Expansion Board+4x A4988 Stepper Motor Driver
1 × 172 SAR Subtotal: 208 SAR
if you will not use External Power please be sure this jumpers are soldered as below :

so after soldering it will be like this image

All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components