What are necessary procedure in calculating subnet mask or simply subneting show an example forr calculation?

To calculate a subnet mask, first determine the number of subnets needed and the number of hosts per subnet. Use the formula (2^n \geq \text{number of subnets}) for subnetting and (2^h - 2 \geq \text{number of hosts}) for host calculation, where (n) is the number of bits borrowed for subnets and (h) is the number of bits left for hosts. For example, if you start with a Class C address like 192.168.1.0 and want 4 subnets, you would borrow 2 bits (since (2^2 = 4)), resulting in a subnet mask of 255.255.255.192 (or /26), which allows for 62 hosts per subnet.