1.

Open Algebra View and Graphics View under  View in  Menu.

2.

Draw your triangle. If you need instructions on how to do this, you can read GeoGebra Instruction 3 here.

3.

Draw at least two of these points:

• the circumcenter of the triangle,

• the centroid of the triangle,

• the orthocenter of the triangle,

using the instructions in the appropriate section.

4.

Select the Line  tool, which is under the third tool, then second in the list. Click the two points from the previous step.

The resulting line is the Euler line of your triangle.