Charts in the pattern are followed using intarsia technique when changing color (when it makes more sense to strand a color, you can do that, too).
All pentagon triangles decrease at the end of every row after row 2 (k2tog on odd rows, p2tog on even rows). Equilateral triangles decrease irregularly: read the charts. See pattern for further details and recommendations.
It is recommended to sew triangles together as you complete them, according to the diagrams given. Put each hemisphere together separately.