Use the compass. Place the point of the compass on Q
Draw an arc that intersects the lines of the angle. ( the arc should intersect lines PQ and RQ)
Step 2.
Locate the place where the arc intersects line PQ, put your point on the intersection, and draw another arc that is a little bit bigger than half of the angle. Do the same for line RQ. (the result should be that the two arcs you just drew form a curved x. The arc that you drew in step 1 also should be running through the middle of your x)
Step 3.
You now should have a total of three arcs. Find the point where all three arcs intersect, and draw a line from the point to point Q