。
She wove grass to make a box.
Literal
She [topic-は] grass [object-を] wove-and box [object-を] made.
編む ('weave, knit, plait') applied to grass forms the basic action; the te-form 編んで links it to the resulting craft — 'weaving the grass, made a box.' Worth noting that a woven 'box' (a closed-lid storage container made from grass or bamboo) is a real craft item — such items are stock crafts in traditional Japanese countryside, alongside woven baskets, mats, and food containers.