How to construct Euler's line???

Anybody know any good websites or can just explain how to construct the orthocenter centroid and whatever else is in Euler's line????? Im Soooooo confused!!!!

Euler's line:

http://en.wikipedia.org/wiki/Euler_line

Orthocentre:
http://constructions.homestead.com/files/ortho/orthocenter_construct.htm

Centroid:
http://constructions.homestead.com/files/centroid/cons8.htm

nine point circle:
http://www.mathsisgoodforyou.com/topicsPages/circle/ninepointcircleconstruct.htm