Before doing anything, you should have a clear plan.
Tips
history
This idiom comes from the Song dynasty painter 文与可 (Wén Yǔkě), who was famous for painting bamboo. Before painting, he would visualize the complete bamboo in his mind (chest), so every stroke was confident and precise.
memory
Chest (胸) + have (有) + complete (成) + bamboo (竹) = having a complete bamboo painting in your chest before you start. You've already got the plan inside you.
