Refer to figures. 
EASA learning objective 022.06.02.01.12 states: 'Define the control wheel steering (CWS) mode as manual manoeuvring of the aircraft through the autopilot computer and autopilot servos/actuators using the control column/control wheel.' 
 

to control the nose wheel steering during low visibility take off and landing → INCORRECT.  Control wheel refers to the type of control column/yoke that's found on the Boeing 737 and similar aircraft.  It does not refer to nosewheel sterring control.

to control the nose wheel steering during automatic landing → INCORRECT. Control wheel refers to the type of control column/yoke that's found on the Boeing 737 and similar aircraft. It does not refer to nosewheel sterring control.

To allow the pilot to manually manoeuvre the aircraft through the autopilot computer and actuators using the control wheel →  CORRECT.  As stated in LO 022.06.02.01.12

to capture and hold the altitude selected with the control wheel on the mode control panel → INCORRECT.  Control wheel refers to the type of control column/yoke that's found on the Boeing 737 and similar aircraft, it is is not a device on the mode control panel and it's not for capturing and holding altitude.

Control Wheel Steering (CWS) is an autopilot mode which allows pilots to manouevre the aircraft, via the autopilot actuators and servos, using the control column (control wheel) rather than using the lateral and vertical guidance modes on the mode control panel (MCP). CWS is a Boeing 737 system but can also be found on similar aircraft with conventional flying controls.

On a B737 CWS can be engaged in both pitch (P) and roll (R) by selecting the CWS button on the MCP or selectively in either pitch or roll by moving the contol column while the autopilot is engaged. The CWS modes are displayed in yellow in the FMA on the PFD.

When CWS P and CWS R modes are engaged the autopilot will simply maintain the current aircraft attitude, any lateral or vertical guidance modes selected on the MCP will be ignored but will still be displayed on the flight director. To manoeuvre the aircraft in pitch and roll the pilots use control column inputs proportional to those used in manual flight and autopilot control is temporarily bypassed. 

As soon as control column pressure is released the autopilot will maintain the selected attitude, therefore the feel and control response will be different to manual flight. Excessive control inputs should be avoided as this could overide the autopilot servos and cause the autopilot to disconnect. 
The use of CWS can be advantageous in turbulent conditions and can be useful at other stages of flight, in some ways it's similar to fly by wire aircraft where the aircraft will maintain the attitude when you let go of the stick.

There are some flight phases where CWS can't be used: 
• Below 150 ft RA with the landing gear down 
• Below 400 ft. 
• After VOR capture with TAS 250 kt or less. 
• After LOC capture in the APP mode.