To apply for a labor license for 300 members to work on the power plant construction in Raigad, Maharashtra, you need to submit the application to the Labour Department office in Raigad. The challan for the labor license fee can be paid at designated banks or online through the Labour Department's portal. Ensure all required documents, such as proof of identity, address, and the number of workers, are in order before submitting the application. Once the application is processed, you will receive the labor license, allowing the members to work legally on the construction project.