Clean the spots for the triangles on the wall with pure alcohol or water, removing all dust or grease. You will need three areas with two triangles each, one for the holder on top, two for each shelve.

Unless you live in your own home, anyone riding a bike faces the question of where to put your bike? Why not securely place it on a wall right in your apartment? Not only is it safely out of the way, it also makes for a pleasing bit of decoration.