How to use the yellow board of armyworm, please recommend a professional way to use it.

I only know that the armyworm produced by Yun Fei Science and Technology has passed the national patent certification, and the use method is also very simple: 1, which can effectively control the development of pests from seedling stage to planting stage. 2. Quantity: 20 pieces of 24X20 yellow boards per mu. 3. Hanging height: Generally, the lower end of the insect trap is required to be 20cm higher than the top of the crop, and it should be hung at the height of 1.5- 1.8m in the solar greenhouse. 4. Clean up in time: When the yellow board is full of pests, peel it off with a wooden stick or rinse it with water, which can be used many times.