How to get a subnet mask?

When it comes to understanding how to obtain a subnet mask, it's essential to first grasp the fundamental role it plays in network configuration. Could you elaborate on the steps involved in acquiring a subnet mask for a given network? What information do I need to determine the appropriate subnet mask? How do I know if the subnet mask I've chosen is suitable for my network? Furthermore, are there any tools or methods that you recommend for determining and configuring subnet masks efficiently? Your insights would be invaluable in guiding me through this process.