Hi. My name is XXXXX XXXXX X'm happy to assist. Your installer is correct. If your new cable modem isn't a combo unit that provides wireless you will need to purchase a wireless router. You are correct in your planned configuration modem > router > switch > PCs & printers. When you configure your router you'll have an option for connection type to assign the static IP address from the cable company.
As well as your static IP address the cable company should also give you the information for subnet mask, default gateway and your DNS server IP addresses.
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