To use a unit circle, you must know where the coordinates are.
For this problem it is asking you where the sin(11pi/6) is.
You look at the unit circle for 11pi/6.
From here you look at the coordinates.
The x value is the cosine and the y value is the sine.
This means that the sin of 11pi/6 is -1/2.
To find the csc or the cosecant you just find 1/sin.
To find the the sec or secant you find 1/cos.
To find the tangent or tan you find the sin/cos.
And to find the cot or cotangent you find 1/tan.