This is a loaded question because my answer really depends on what you already understand.
I would start by thinking about y=cos(bx+c) because cos is the reciprocal of sec
Now this is obviously a cos graph and hopefully you know the basic shape.
The amplitude is 1 because there is an invisible one in front of cos
The period is 2*pi / b
The phase shift is c/b (left if positive, right if negative)
Once this is graphed you take the reciprocal of each y value to make the new 'reciprocated' graph.
usually try to do it from the limits eg as y approaches 0, its reciprocal will approach infinity and I work backward from there.
Once you have the reciprocated graph you just times all the new y values by a and then it is all done.
EXAMPLE
I have graphed y=1.5*(sec(2x+(pi/4)) to try and show you how it works. I will try to add the graph as an attachment.
Start by considering
y=cos(2x+(pi/4) a=1 (this is the new 'a' not the original one, b=2, c=pi/4 therefore
amplitude=1, wavelength=2*pi/2 = pi = 3.14159, phase shift = pi/4 / 2 = pi/8 This is positive so the graph moves left. (moves neg direction)
Once this is graphed the graph is reciprocated.
Now all the points are multiplied by 1.5 which was the original 'a'.
The graph is now finished.
To think about reciprocated graph try considering y=x which you know is a line and y=1/x which you should know is a hyperbola.
LET ME KNOW IF ANY OF THIS HELPS or if I can clarify anything. I have already fixed one small error there may be more, let me know if you think so.
To draw the graphs for you I used http://rechneronline.de/function-graphs/
compicated sec graph .png
+118654 
