For future reference: When two triangles are congruent they will have exactly the same three sides and exactly the same three angles. The equal sides and angles may not be in the same position (if there is a turn or a flip), but they are there.
If I were you, I would make the starting point (3,-6). From there, you will want to use the slope of -1/2 (go down 1 unit and to the right 2 units and draw a point)