Note: This should only be done if the computer had previously had this set to static, or if it is replacing another computer that was already static.
Navigate to the Windows Network Connections
Option 1: Open the Run box by pressing Windows + R and type in "ncpa.cpl"
Option 2: Open the Start Menu > Control Panel > Network and Sharing Center or Network and Internet (Windows 8+). Then select Change adapter settings.
Right-click on the Local Area Connection/Ethernet option and select Properties.
Select Internet Protocol Version 4 (TCP/IPv4) and select Properties.
Within General, select the option to Use the following IP address: and fill in the IP address, Subnet Mask, and Default gateway.
Note: For Subnet Mask and Default Gateway, we can generally assume the defaults, listed below:
Subnet Mask - In almost all cases this will be 255.255.0.0 or 255.255.255.0, these are known as /16 and /24 respectively. In order to know which they use we can compare with other IP addresses on the network. IE: if the machine currently being used has the IP of 10.10.10.5 and they have another computer on the same network with 10.10.10.4 we can assume they are using /24. If instead, the other computer is using 10.10.9.4 they are likely using /16
Default Gateway - The default gateway will almost always end in an octet of .1; with the preceding digits being based on the Subnet Mask they have. If they are using /16 the Default Gateway will normally be XXX.XXX.1.1 (10.10.1.1 in the above example), if they are using /24 they are likely using XXX.XXX.XXX.1 (10.10.10.1 in the above example)