What you need to know is that all networked devices require a NIC. (Network Interface Card) A NIC has two different addresses. One logical (aka an IP address) and the MAC address. The MAC address can be used for several reasons, Static IP assignment, MAC address filtering, MAC authentication, Device identification, and Device Tracking.
When your device connects to a router with a static IP address, it will always receive a static IP address if there is a matching MAC address. (Routing Table)
When using MAC addresses filtering, your companies network will only allow very specific MAC addresses to connect to their network.
MAC Authentication is where your ISP might require you to authenticate with a MAC address before actually connecting to the internet.
As you can see, spoofing your MAC address allows you to get over quite a few networking obstetrical.
Step 1) Go to Start > Control Panel > Network and Internet > Network Connections >Right click the networking device you are going to work with > select properties
Step 2) On the Networking tab, click Configure. Next, move to the Advanced tab and click on the Locally Administered Address or the Network Address property
Step 3) Looking at the right side, you will see the value but by default is not present is selected. Change that to Value and enter a mac address. It can be a combination of 6 pairs of numbers/characters. Example: 30:A5:b4:14:9C:F2
You will enter the without the colons.
Once finished go to CMD and type IPCONFIG /ALL. After everything checks out, go ahead a reboot the Workstation for the changed to take effect.