Setting up a Static IP Address on Raspberry Pi
This really just involves editing /etc/dhcpcd.conf. The configuration here looks like:
interface eth0
static ip_address=192.168.1.10
static routers=192.168.1.1 # Set this to the router's gateway address
static domain_name_servers=192.168.1.1 1.1.1.1 8.8.8.8 # List of DNS servers, may use router as the only and default