In a typical setup, the modem, or whatever access point you use for access to the outside world, and router are kept within close proximity. So to use a typical Cable internet connected home with say 6 wired ethernet devices the configuration would be...
#1. Incoming cable to cable modem.
#2. Short ethernet cable jumper from cable modem to router.
#3. Short ethernet cable jumper from router to switch (if your wired port need is greater than your router can supply, if not never mind this...)
#4. Long ethernet cables to wired ethernet devices, PCs, security camera systems etc...
If your cable is run through the walls you will want keystones and wall plates in the mix as well as sufficiently sized cables to go from router or switch to wall, then wall to whatever device.