Moldable plastic sheets, also known as thermoplastic sheets, can be used for a variety of purposes, such as crafting, prototyping, and repair. Here are some usage instructions:

1. Heating: First, heat the plastic sheet using a heat gun, hot water, or other heat source until it becomes soft and pliable. The exact temperature and time required will depend on the type and thickness of the plastic sheet, typically 150°
2. Shaping: Once the plastic sheet is soft and pliable, you can mold it into the desired shape using your hands or a mold. Be careful not to burn yourself during this process.
3. Cooling: Allow the plastic sheet to cool and harden in its new shape. You can speed up the cooling process by dipping the plastic sheet in cold water or placing it in a refrigerator.
4. Finishing: Once the plastic sheet has cooled and hardened, you can trim and sand any rough edges, and paint or decorate it as desired.
   

Some specific usage instructions for moldable plastic sheets include:

• Crafting: Moldable plastic sheets can be used to make a wide range of crafts, from jewelry to figurines. Simply mold the plastic sheet into the desired shape and decorate as desired.
• Prototyping: Moldable plastic sheets can be used to create prototypes for products or inventions. Simply mold the plastic sheet into the desired shape and test its functionality.
• Repair: Moldable plastic sheets can be used to repair broken objects, such as toys or household items. Simply mold the plastic sheet around the broken area and allow it to cool and harden.

Remember to always follow the manufacturer's instructions for your specific type of moldable plastic sheet, as different brands and types may have slightly different usage instructions.