Your text book(s) contain instructions on how to perform constructions such as bisecting angles, drawing perpendiculars etc.
However the exercises they give are normally fairly dry. These pages show you some constructions you can apply those skills to and are hopefully a little more engaging.
This construction circumscribes a triangle, ie draws a circle that passes through all three vertices of the triangle.
To carry out this construction you must first construct the perpendicular bisectors of the three sides to find the circumcentre (this may be outside your triangle - don't panic). Then draw a circle, centred on the circumcentre that passes through all three vertices of the triangle.
Instructions on how to construct a perpendicular bisector may be found here.