Hi Kendra.
I would start with a diagram something like the one below and label it with letters so I could refer to it in the proof:
Now you can state what is given:
 Line FB is tangent to circle O at A
 Line CE is tangent to circle O at D
 Line AD is a diameter of circle O
And what you are to prove:
Line FB is parallel to line CE
And formulate a plan for the proof:
 Show why OA is perpendicular to FB and OD is perpendicular to CE
 Show why angle EDA is congruent to angle BAD
 Show why angle EDA and angle BAD are alternate interior angles of the transversal AD across lines FB and CE.
 Conclude that this makes FB and CE parallel.
A twocolumn proof is one where the left hand side gives the mathematical statements based on given information or on information from earlier steps in the proof and the right hand side contains the reason why this step makes sense. The reasons are generally either "Given", some kind of definition of terms, known theorems you can apply, or logical deductions that follow from the earlier steps. The proof ends with a statement of what you were trying to prove of course:
Statement 
Reason 
 Line FB is tangent to circle O at A
 Line CE is tangent to circle O at D
 Line AD is a diameter of circle O

Given. 
 FB is perpendicular to the radius AO
 CE is perpendicular to the radius DO

Definition of tangent. 
 angle EDA is a 90 degree angle
 angle BAD is a 90 degree angle

Definition of perpendicular. 
 angle EDA is congruent to angle BAD

Definition of congruent. 
 AD is a transversal of the lines FB and CE

It crosses (intersects with) them both. 
 angle EDA and BAD are alternate interior angles

Definition of alternate interior angles. 
 line FB is parallel to line CE

Known theorem: If any two lines are cut by a transversal such that alternate interior angles are congruent, then the two lines are parallel. 
And that's how you do a geometric twocolumn proof.
Cheers,
Stephen La Rocque.
